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CrossBow

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  1. CrossBow

    Sega Master System - FM upgrade Region Switch Info

    By CrossBow,


    Ivory Tower Technical Info & Notes
    I've installed the FM upgrade board 4 times now into a few different SMS NTSC consoles now and something that I tend to always forget, is that the official instructions for installing the board has a few mistakes in it. One of those mistakes is a pretty big one that I've mentioned to Tim Worthington a few times but it never seems to get fixed in his guide. That step is regarding the process for getting the region switch working on NTSC consoles. Now the steps listed I'm sure are accurate for PAL versions of the console, but 3 different model 1 and one model 2 unit I've installed the kit into all required the same thing to get it working.
    The specific step to install the region switch wire states to solder a wire from the IORQ pin off the FM board and to isolate and solder the same signal pin on the 2516 IC chip in the console. This chip is the IO Gate array IC btw. The docs state this is pin 19 on that IC and that is a correct statement. However, removing this pin from circuit on the NTSC consoles will prevent the SMS from booting at all. Just a black screen when powering on the console. Attaching the region switch wire to that pin while isolate does nothing.
    The pin you want to attach to instead on that IC is actually Pin 23. It is listed as the KillGa pin and I assume has something to do with a halt or reset. In some models of the SMS pin 23 isn't attached to anything. But on the NTSC systems it is part of the circuit. So, you have to either cut the trace to this pin or lift the pin from the board to isolate it and then install the IORQ wire from the FM board to pin 23. This will correctly allow switching the region on the SMS. The region switch isn't dynamic so you have to either reset the game after switching, or power the SMS off and then back on for the region switch setting to take effect. Here is a picture of the wire I'm talking about attached to a lifted pin23 off the IC I did the other night as an example.

    Here is the IORQ pad the other end of the wire attaches to on the current and latest version of the FM board upgrades. Depending on the version of the FM you have, this pad has changed places but it is always labeled the same. In the pic below is the yellow wire soldered on the upper left section.

     
    So if you ever install one of these or possibly have one installed and hadn't gotten the region switching working on your NTSC console, now you know why and how to correct for it.
    BTW the switch is advised because it allows you to select between US/PSG audio, US/FM audio, and JPN/FM audio settings. There are 2 games known that require the JPN/FM setting in order for them to work with the main one being Wonder Boy III: The Dragon's Trap here in the US (Wonder Boy II in JPN).
     
  2. CrossBow

    Atari 7800 :- Controller remote pause function modification

    By CrossBow,


    Ivory Tower Technical Info & Notes
    This is something I've messed with on and off again over the years. After I discovered the controller pause modification you can do on the Sega Master System, it got me to thinking if something similar was possible on the 7800. And yes, it totally is as similar to the SMS, the pause line on the 7800 is always active and only when pulled low to ground does it trigger the pause. So I had played with it a bit using home made perfboard setups etc. But it wasn't really as useful or needed on the 7800 as it is on the SMS so I hadn't really invested much into it.
    For those that might not be aware, the Master System also uses a 2-button controller like the 7800, but the SMS also has a pause button on the console itself just like the 7800. The difference it that many SMS games actually use the pause on the console as a 3rd button to pull up inventory or stats..etc. in quite a few games. As a result, playing those games can be a bother when you have to get up and press the pause on your console each time you want to access those extra functions in the game. So naturally a modification for the SMS was going to come about to allow a person to add a 3rd button to their controller and along with a simple logic circuit in the console, you can make impossible controller combinations trigger functions inside the system. In the case of the SMS it is using an extra button to trigger either an Left+Right direction combo, or Up+Down depending on how you wire it up. That in turn is fed to a logic OR gate so that when you press that button on the controller it sends that impossible combination to the chip and that in turn will trigger the reset function. 
    The 7800 sharing essentially the same setup here can also be done in the same manner. However, due to the 2600 and 7800 internal logic regarding the paddles controllers; you can't use the Left+Right combo because it will confuse the console and sometimes thing paddles are plugged in. But aside from that, it is the same. 
    Consoles Unleashed in the UK sells a lot of excellent quality modification and upgrade kits for various consoles. One of those they have the most kits for, is the Sega Master System. They provide their own pause button modification kit that is really well made and looks nice. Well, I ordered up a few several weeks back and got them in yesterday. I immediately went to work on installing one into my personal 7800 as I have 2 controllers that I've modified in the past to be able to use this setup. Here is what that looks like:

    As you can see it is a tiny PCB that will fit in lots of places on the 7800 main board. Again, it is designed for the SMS but will work just as well in the 7800. In the pic above you can see that I'm getting power and ground from the bypass cap just to the right of the 6502. The Player 1 Up and Dn connections are at the top of those two resistors right next to that cap. So you have half of what you need right there in that spot. 

    Above is where the rest of the connections in my setup are going. The small blue wire that runs by itself to that single point below the RIOT IC is the reset trigger. This is an unused via that is present on every single 7800 main board revision I've see and always in this same spot. I assume it was there for testing but is also makes a great place to attach the PB pad from that board to trigger the pause function. The other two blue wires are going into cleaned out unused vias so they pass back down on the bottom of the board to attach to a similar set of resistors for the player 2 Up and Down connections. I did it this way because I didn't want to trim the RF shielding. The resistors are outside of the shielding for the player 2 controller port next to the Reset switch.

    And this is where the two wires come back through to the bottom of the PCB to attach to the resistors mentioned above. BTW, the Up and Down combo wiring attaches to Pins 1 and 2 on the controller ports.
    And that's it! Now with this in place, I can use my modified controllers to remote activate the pause on the 7800 console from either controller port.
    One thing to mention about using this kit from Console's Unleashed...
    You have to wire both controller ports! The reason is because instead of using an OR logic in this setup, they are using a NOR logic chip. As a result, the controller ports are always registering high. If you don't connect up the second set of wires, then the logic on the pause board in the kit ends up triggering the pause constantly. It needs to see that +5 from the port pins in order to maintain the logic. So if you only wanted one port to activate this, you need to use a different logic IC. Also, the kits from consoles unleashed has extra stuff I don't normally need as it comes with additional small PCBs to mount a 3rd button to and provide as a template to drill the hole into your SMS controllers for mounting it. An excellent touch to be sure, but I don't like the SMS control pads compared to other controllers and wouldn't be using them on a 7800 anyway. But they aren't that expensive and I might need those boards in the future so who knows? I might go into details on what is required on the controller side someday for this modification to work as there is work required in the controllers. I think I've covered it elsewhere online but might do that as a follow up someday.
    Here is a link to Consoles Unleashed in the UK and again, they have some excellent quality kits on hand to help modders and tech with making their projects look that more professional and easier to install.
    https://www.consolesunleashed.com/
  3. CrossBow

    7800 oddity - a Maria that kinda? Works?

    By CrossBow,


    Service Work Stories
    Had a 7800 come into the ITC lab to get refurbished, and upgraded with a few things. Among the updates was to get a UAV plus mount board setup as I've been doing for over a year now.
    This is where it is important that you always...ALWAYS test the current status of electronics before you dive in and start doing stuff. A rule I didn't follow so what I discovered after putting all this work in, isn't something I could verify was an issue before the work started. I had been told that it was working 100% without issue as it was the daily driver 7800 for the owner. 
    So what was the issue I discovered? Well, after installing the UAV setup and the 10pin mini din AV connector to test the system. I saw something odd when I ran Ballblazer for burn in testing. What I saw was odd additional background graphic information on the far left and far right sides of the screen that I'd never seen before? More specific...this is what Ballblazer looked like:

    So if you look on the left and right hand side of the image, you will see what looks like the blue in the sky being extended out along with some burgundy like brown/red below that. Now oddly enough the 5200 version of the game through a UAV actually looks kinda like this, but on the 7800 this isn't normal. Here is a closeup detail of the effect and you can see it is more like a checkerboard pattern within those extra graphics being shown.

    Making matters more confusing was that NOT everything had this effect going on. Ballblazer seemed to show it the worst but any game using a colored backgrounds would have this kind of effect going on. But anything using a black ground was fine as this color hue test screen shows from the 7800 utility program:

    I did figure out pretty quickly that the issue had to be something with the Maria IC because this same effect wasn't happening on 2600 games and was only present on 7800 titles. So a few days of delay (Waiting on a new heater for my desoldering gun), I removed the original Maria IC, installed a pair of new 24pin sockets (As I don't have 48pin on hand). And installed a different Maria pulled from a parts donor 7800. And what did ball blazer look like after that?

    It worked! So yes after nearly 150 Atari 7800s that I've worked on, this was a first. My guess is that this 7800 always had this issue but as it was mainly used on a CRT and was only present on 7800 games, it likely wasn't noticed or the owner simply thought it was normal. In any event the original Maria was working in that the actual game play area on the screen looked normal otherwise. But the blanking to mask the extra graphics junk on the sides, wasn't working properly on this Maria and only by swapping it out with another was the issue fully resolved.
     
  4. CrossBow

    New PCB Design for Intellivision installs - Sample install pics

    By CrossBow,


    Ivory Tower Technical Info & Notes
    I already made a blog post not that long about about my new designs and had posted pics of the render of the PCBs. Well, I actually received the PCBs in the other day and have had a chance to test them out. While I did make a pretty big blunder on my model 2 specific PCB, it was easily fixed and isn't that big a deal to fix in situ when installing. And it only affects me since the gerbers that I play to release publicly already have the fix in place so future boards that get made up should be good to go.
    A quick recap on these PCBs. It is a total of 3 different boards. The bottom base PCB is the same for both original 2609 model and INTV 2 model consoles. I designed it that on purpose. So what is different between the models is the top PCB that you use as they are specific to the model of the console you plan to use them in. These mounts are designed to be installed in place of the RF modulator so that a 'No Cut' option is able to be achieved when upgrading your Intellivision.
    Here is a mock up the 2 PCBs put together for the original 2609 model of the console. This is essentially an upgraded extension of my original older mounts that is easier to install and secure into place vs the older mount PCBs I've been using. The top PCB has a large solder section on it so that the mini din jack that is used can be more easily be quick tack soldered into place to test alignment and fit before flood soldering all around the jack to secure it into place. While the mini din is technically being installed upside down in this fashion, it is important to know that the actual 2609 style mainboards install upside down to begin with. As a result, the mini din is actually right side up in the end.



     
    The model 2 setup was much more difficult for me to design and I really gave my calipers a workout making so many measurements. So the main difference with the INTV 2 setup is that the bottom base mount PCB (Again it is the same on both models), has cut outs on one corner of it. This is because the top board of the INTV 2 mount actually has you solder the mini din direct to the PCB like it would be normally. The cutouts on the bottom base PCB allow for room for these soldered pins off the mini din to come through and allow the two PCBs to sit flush together. It does require that the pins and ground tabs be clipped fairly flush to the PCB once soldered to make sure nothing sticks out beyond the bottom PCB where it would likely then short on the large ground plane that the RF modulator was sitting on. But this isn't a big deal and the end result is a nice finished mount where the mini din is again able to be right side up when all put together. Previously, the mini din was actually upside down on the INTV 2 installs. So this will be less confusing for people going forward.
    Here is a detail showing the two sections assembled. You can see the cutouts on the bottom base PCB to allow for the soldered pins of the mini din to come through. So this means that you need to solder the mini din to the top PCB first.

    When you cut the soldered connections pretty flush to the PCB the mini din was soldered to, it will ensure that the soldered connections and pins don't come through to cause any issues below. Here you can see where I trimmed an applied fresh heat to the joints after to be sure everything was secure and wouldn't cause any issues with shorts.

    Like mentioned before, the entire PCB assembly is designed to install in place of where the RF modulator was located. Here you can see how that would look internally. There are solder pads provided on the PCB for all the needed connections. There are 2 sets of RGB pads that are to be used depending on if you use the 8-pin or 9-pin part of the PCB. Yes, I designed it with through holes for both types of commonly used mini dins for RGB installs like this. There are 3 pas in the center that are shared between both mini dins. Those are the +5, Sync, and Audio. In the picture below I used an 8-pin mini din. So you can see the space in the opposite corner for the 9-pin through holes that weren't used in this install. You can also see the pads specific for the 9-pin that weren't used. The blob of solder on the mini din is part of what I have to correct for on these first set of PCBs but won't be needed on future ones.

    And once in place, it should be centered pretty well in the spot where the RF used to be allowing for plenty of room for your cables to be plugged in without any modification of the case. Again, a 'No Cut' option is achieved. Ignore the switch below this as that is needed for something else since this INTV 2 uses an older RGB setup.

     
    So again, the plan is to release the gerbers for these publicly so others can have them made up for their own installs. I've already had a few other modders reach out to me wanting the gerbers because they actually want to change out their current mounting to use of these new setups. 
  5. CrossBow

    New PCB Designs & New Option for UAV Installs Soon!

    By CrossBow,


    Ivory Tower Technical Info & Notes
    For the past several weeks on days where I have some off time from other console service requests, I've been designing up some more new PCBs to assist me in the services I provide for folks. 
    I know I recently posted about a new PCB mount for the Intellivision and while I do have those new mounts in place, I wanted... more. So I designed new ones that are currently on their way to me. It is a 2 piece PCB design that uses a thicker bottom PCB as a base that can be used with either model Intellivision console. There is a section that is cutout on this base board so it can be used with one of the 2nd piece top boards it pairs with.

     
    As stated earlier the bottom board is paired with a 2nd top layer board. Depending on the model these boards are slightly different from each other. Here is the top board that goes with the model 1 Intellivision. It uses a solder plane that allows for the mini din jack chosen to be installed anywhere within the solder region. This is because there can be some slight variance between the model 1 case shells and how the main boards line up inside them. The mini din jack is soldered into place upside down because the main board of the model 1 intellivision is upside down normally. So when all assembled, the mini din would actually be right side up.

     
    The other 2nd top board is specifically for use with the model 2 intellivision. This one use the cutouts made on the bottom base board. If you can visualize how this works, the mini din is actually soldered into place facing right side up on this board. And then when the top board is attached to the bottom base, the cutouts allow space needed for the soldered pins of the min din to come through to allow the two boards to sit flush. It requires having to trim the soldered pins to be as flush with the pcb as possible before attaching the two halves together but that is a minor thing. It is designed for both 8 or 9pin mini din to be used. You only have to turn the board to orient as needed for whichever mini din style is used.

     
    I'm hopeful these new PCB designs even as simple as they are, will allow for a more professional looking and less labor intensive install for the mini din jacks going forward. The fact that the top board for the model 2 allows for the jacks to be soldered the top board, means that the mini din will be right side up on the model 2. Currently the way they are done means they are upside down and that can be confusing.
     
    Now, after messing around with these and having done a few RGB upgrades into some other consoles using different kits. Someone made it known that there is a mini din I could be using to do the same thing on my UAV installs on Atari 7800 consoles?! Sure enough, using a 10pin mini din and wired up for Sega Saturn cables, you can get all of the video signals that a UAV can offer onto a single jack plus the audio. And... it would require very very slight modification to the case shell offering a near no cut solution. I say near no cut because in order for this to work, it does require that the RF opening be widened a tad to allow for the cable insulation to come through easily and allow for the cables to be fully seated into the jack. But here are some teaser pics to show a mock up of how this would look. I think offering this going forward will be a nice option for those folks that don't want all the holes drilled into the case shell and would prefer their 7800s to look as stock as possible. While this would still require the slight modification to widen the opening for this to work, I think this is a compromise that many would be okay with. These pics are a mockup of how it would look. I used an 8pin mini din to test for this so what you see isn't the actual mini din that would be used.

     

     
    It will use a new breakout PCB specifically for A7800 purposes. It could be used for other projects, but only the signals and pads are in place for composite and s-video, audio connections. While all of my installs use a mono audio setup, I did go ahead and leave the pads separate for Left and Right and placed a jumper in the PCB that can be bridged with solder to make it dual mono output. In that case, the jumper is soldered and only one of the audio pads needs a wire soldered to it.

     
    So yeah, been a busy few weekends working on these designs and ideas. Everything has been ordered and hopefully in the coming weeks I can show some better examples. I'm especially excited for the new 7800 mounting using the 10pin mini din, as it will also greatly reduce the labor time needed for UAV installs. It does add to the parts cost a little, but when combined, it all washes out so I don't have to change my flat pricing I already offer.
     
  6. CrossBow

    Latest stuff at the ITC

    By CrossBow,


    Service Work Stories
    I know I've not made a video in a very long time on my ITC Youtube channel. But I figured I would mention here the latest things happening at the 'Tower'. Just because there haven't been any vids uploaded, doesn't mean there isn't something always still going on.
    First is that console service requests have picked up quit a bit for me over the past 2 years. It really started during the pandemic, but then larger and larger service requests started to come in since and at this time, there is pretty much always a console or 3 at the 'Tower' waiting to get serviced it seems. When not working on enthusiasts game consoles, then I use that time to work on my own consoles to improve old install work I did in them (Some going back over 10 years ago). 
    Well, currently what is at the ITC to be serviced is essentially done and will be getting shipped out soon, but as we had some pretty inclement weather come in this past Sunday and as a result our offices were closed at my normal day job yesterday. I spent the time to finally design some new PCBs for use in my services. One isn't that big a deal but is my own pcb breakout for use with 9-pin mini din connectors. I've got an old gerber file set that I either found a few years back or was sent to me that I've been using. But decided to make my own with some slight alterations on the design I'd been using. Not a big deal so not really anything to show there.
    But, I also finally designed revision 2 of the 7800 mount board. I already had another slight revision that I was calling r1b for the past 6 months but decided to just add in one new feature to make it easier in the future as I'm now getting requests for it. The new feature is adding in an optional audio input pad with resistor onto the mount board that can be used to mix in a 3rd audio input source into the 7800 setup so that it along with the normal audio can all be heard from the RCAs or whatever is used for the audio output on the console when upgraded. I'd been doing this manually by just adding in a resistor in series on separate wiring that would then get soldered to the + pad on the output filter capacitor. It works but I like how this will look better and I don't have to hide a resistor to solder in place anywhere and can just run a wire straight off the pad to the jack used for audio input.

     
    The other project I worked on yesterday was to finally design a new mount board setup for use in the Intellivision RGB installs. I previously designed a small mount PCB about 2 years ago for this and that will still be needed and used in some circumstances. But more and more lately, most of my clients have me remove the RF modulator and install the mini din jack there for the RGB output. This is because with a PCB of the right height, you can place the jack here without having to cut the case. The current PCB mount is kinda difficult to install as it requires a lot of heat to ensure that the solder seeps it way under the PCB and has always been a little smaller than I'd like to help provide the needed anchor and support for the mini din. Well, after installing a few other difficult kits into consoles designed by others, I decided to adapter something similar. This new mount is larger and uses 2 of the original intellivision RF anchor holes that I run clipped leads through some vias to solder the mount board into place easier with less heat and possible provide a more secure mount as a result. It does actually use a 2 PCB setup to achieve the height needed but I've found that 2 PCBs in a stacked configuration is still going to be much easier and cheaper to have made. The older mounts were 2.6mm thick PCBs and as a result, they weren't cheap to have made. Using a 2 board solution will also similar results with less cost. I will be refining this further. But this is the top PCB that the mini din will fit into the lower right corner section and then be held in place with solder along the two large ground planes along the left and rear of the jack. Both PCBs feaure hashed ground planes to help with strength. The top logo and wording on this PCB are now silkscreened but in fact are done by removing the solder mask over a copper filled section of the PCB. This way the logo and words have a shiny look to them that is actually part of the PCB and not just silkscreen that can wear/rub off.

    So, yeah all of these and other parts on order now and I'm excited to see how it all looks and works first hand.
     
  7. CrossBow

    Player 2 auto triggering fire button...again!

    By CrossBow,


    Ivory Tower Technical Info & Notes
    I already touched on this in an earlier blog post not that long actually, but I will summarize again really quickly.
    Main issue is that in 7800 mode and games, one or both fire buttons might show as being pressed without a controller plugged in. Plug in a controller and everything behaves as it should but ultimate, the console shouldn't read anything actively from the ports without a controller plugged in.
    In my previous blog, I mentioned that an out of spec resistor located at R35 was only reading about 217Ω while the schematics state that this resistor and the on next to it, should be reading 220Ω. Most of the resistors in the 7800 I believe are 5% tolerant meaning that the value of the component should read within +|- 5%. In this case, such a resistor would still be technically in spec if it were reading as low as 209Ω or as high as 231Ω would still be within that 5% tolerance. So a resistor reading 217Ω is well within the tolerance spec of the resistor.
    This was likely fine years ago when everything was much newer, but it seems as the equipment begins to age, these values become more and more tight and the tolerances allowed will no longer work.
    Because to fix this 7800 over the weekend, required that I again find a replacement resistor that was reading closer to 220Ω to resolve the issue. In this case, the resistor reads 219Ω.
    I've attached a picture that shows the location for these resistors. R34 affects player 1 and R35 affects player 2. And again, these resistors only seem to come into play as causing an issue when the console is in 7800 mode. You can actually remove these resistors and the 7800 fire buttons will still work properly on 7800 games. But they will not work in 2600 mode. So the resistors are only needed for 2600 mode but if will actually effect 7800 trigger readings once they get to a certain threshol.
    To be fair I don't think these resistors are just suddenly now starting to read off spec. I suspect the issue is actually the TIA starting to show signs of failure internally as swapping out TIAs will also fix this. But for now, with TIA being much more expensive to replace than a simple resistor, I'm going with changing out resistors to be more in spec going forward and I might just start stocking up and replacing out R34 and R35 with 1% types as part of preventive measures.
     
  8. CrossBow

    Atari 7800 Powering On / Off issues...

    By CrossBow,


    Ivory Tower Technical Info & Notes
    As stated in another blog, I have a few 7800 sent to me for repairs and eventual upgrades. This 7800 had an interesting problem where as soon as you plugged in the DC power to the console, it would immediately power on and would NOT turn off. While there are a few components in the mix that can cause, this, I've found really only two components well technically 3 that should be looked into as possibilities:
    The first component and the one most people already know about, is the power switch itself. But in this particular case, it wasn't the switch as the console would still power on even with the switch removed.
    The next component is the 4013 IC flip-flop. This chip controls the actual on or off signals sent through the console when you press the power button. However this had already been replaced in the past as on this console it was mounted in a socket. Removing the 4013 did NOT change the condition on this console and it would still power on immediately. This pretty much only leaves one more component...
    There is a large transistor mounted in spot Q10 and labeled as an MJE210. These were used on both the 7800 and the 5200 that I know of. This transistor receives a signal from the 4013 telling it to actually switch the unregulated power over to the 7805 voltage regulator. I quickly found out this was the issue when I removed the 210 and the issue went away. This was replaced out using another one from a donor 5200 parts board as the 5200 actually has a pair of these bad boys on them. Here is what the MJE210 looks like. In this picture, the failed one is the green one on the mat and replacement from a 5200 has been installed into place. These only work installed in one direction and that is usually with the MJE labeling facing towards the back of the 7800.

     
    So yeah, if you have power on/off issues those are the three main components to check for first as the other components are mostly passives and not as likely to go bad.
  9. CrossBow

    Very dark and poor RF output? Look to the 74LS32 IC...

    By CrossBow,


    Ivory Tower Technical Info & Notes
    A few 7800s have been sent to the ITC for repairs and eventual upgrades. Before any upgrades are done, I always get the consoles back to fully working stock condition first. This 7800 was working but had very dark, fuzzy, and as such very poor RF output. Now yes, RF output doesn't look that hot on modern displays to begin with, but this was obvious something was wrong. After looking over the board for a bit, it became apparently that someone in the past had replaced or tried to replace the 74LS32 IC chip that resides just above the Maria IC on the 7800. This chip handles quite a bit of the output signals from the Maria and through to the RF section so this chip not working or being faulty will produce no picture output conditions, scrambled looking picture output or similar video output related issues.
    Upon removing the chip, I quickly found 3 main problems as the cause and they were all due to poor connections due to damage from when the chip had been replaced prior.
    Here is a picture of the top of the board with the spots identified that were the issues.

     
    I will state that the bottom of the PCB actually looked much much worse with lots of burnt PCB marks indicating that perhaps much too high a heat was used when trying to remove this chip originally. But, only a single VIA pad was  damaged on the bottom and wasn't connected to anything so it wasn't critical damage.
    I used three very small sections of 30awg solid wire kynar to repair these broken trace sections. I then placed a new socket on top of it all and then soldered it all back down into place. The original 74LS32 tested good on my chip tester so it was put back into service in the new socket and now everything is good to go! BTW, while a UAV install would bypass a bit of these signal lines, the sync and Lum1 are processed through this chip and so if that chip is faulty, it can result in affecting or preventing output from AV upgrades as well.


    So yeah... if you find yourself with some squirrely looking RF output but can still kinda make out a picture, you might look at this IC as being a possible part of the problem. Again, in this case it was due to what I assume was the chip being replaced out in the past, but whomever did the previous work damaged some of the traces and via pads in the process making the replacement not making contact where needed.
     
  10. CrossBow

    Weird Paddle 3 issue on a 2600 4-switch?!

    By CrossBow,


    Ivory Tower Technical Info & Notes
    I've seen something similar to this before although not in the way I was seeing with a recent 4 switch console I was servicing. As part of diagnostics I will use Paul Slocum's excellent Test Cart program as it should some primary colors, shows the current state of all switches minus power of course, but also has a basic graphical view of each controller and small block on the bottom that will move left/right when you plug in paddles to test those too. So all in all a nice utility to know that all controller functions are working properly on the console.
    Well, on this one, player 1, player 2, and player 4 paddle controls would move from left to right and back turning the paddle as you would expect. But player 3 paddle control would just site on the left side, and then after a point when turning the paddle, it would suddenly just be on the right. No movement of any kind. Just one sec on the left, and then next thing you know it is on the right. So it was acting more like a digital control vs analog. It wasn't the paddles since I used the same set to test player 1 and 2 and that was working fine.
    Going through the service manual will yield some interesting stuff to help isolate this, but unless you have the diagnostic controller plugs and the 2.6 diagnostic rom, you aren't going to be able to see exactly what you need to see. But lets review that..
    If you have the diagnostic plugs, plugged into the controller ports and the diagnostic rom up and running with the controller matrix screen up. Then you use an Oscilliscope to probe the paddle lines off the TIA pins 37,38,39, and 40. They represent player 4, 3, 2, and then player 1 on pin 40. Well, what you should see on your scope if you have it set to the right settings, is something like the picture below from the service manual:

     
    However, when I probed pin 38 that is for the player 3 paddle line. I was getting a flat line. Well, actually I was showing a flat line of about 1v but the point is...not pulse like you see in those pictures. (And btw...I was seeing that same pulse line on my o'scope for the other paddles). 
    Well honestly there isn't much in the way of electronics from the controller port to the TIA where the paddles are read and handled. In fact, there is really only 1...just 1 component in the middle of the mix from the controller port to TIA. At least on the 4 switch and above units this is the case. That one component is usually a small ceramic disc, or poly capacitor that doesn't usually go bad. So I first checked that the traces from pin 5 of the player 2 controller port to that cap (C220) was good. It was, and then checked from the cap to pin 38 of the TIA. That too pinged out good. So I went ahead and replaced the capacitor just to see if anything changed. Sadly.... no.
    What did fix it?
    Well, if you've gotten this far and read my description of the very simple circuit from port to TIA... it should come as no surprise that is was the TIA itself. This is even more sad considering how rare these IC chips are now becoming and there isn't any projects I'm aware of to make new ones or something to replace the TIA. 
    But yeah... if you find the paddle lines aren't working, chances are that it is the TIA chip itself that has failed if the actual traces are good. Apparently this was less of an issue with earlier 2600s as they used buffer ICs to help control this and therefore the TIA was more protected. Just more cost cutting at work as the console lived on...
     
     
  11. CrossBow
    Received my BBPro 7800 adapter today and we have some really good things and some not so good that I'm hoping can be worked out in time.

    - First the good, is that the menu of course is easy to navigate working in the same manner
    - This might be the fastest loading flash cart for the 7800 with the exception of the older Mateos cart
    - Plays the many of the original released games without issues including both Commando and BallBlazer with properly balanced and proper sounding Pokey audio! Nice!

    Now for the issues I've encountered...
    - None of the 2600 roms I've tied to load up will work. What happens is that the 7800 resets after selecting the game and then essentially crashes. Now, I actually have a modified BIOS installed into my 7800 that was developed by Pac-Man Plus (Bob D.) and RevEng that plays the Kiloparsec build in 7800 game when it doesn't detect a cartridge installed. However, in the case of the BBPro, whenever I try to load up any 2600 game or some of the more recent 7800 home brew releases, it will default to the Kiloparsec built in game.
    - Some of the more recent 7800 home brews that I've been testing, will load up, but the audio isn't quite right on their POKEY sounds and the graphics glitch quite a bit with horizontal flickery lines.
    - One of the home brew games I have is E.X.O. in its full ready to be released form. It is a 512kb game but it doesn't load and causes the 7800 to load up the Kiloparsec built in game in my console again.
    - Doesn't seem to support Pokey at $450 or $800 which are somewhat newer implementations of Pokey addressing. So it seems it only supports Pokey at $4000and $8000 is my guess?

    Here is the list of original released titles I've had trouble getting to load up. These were all taken using Trebor's rom pack"
    - Ace of Aces will load up but no audio and corrupted graphics
    - Basketbrawl just gives a black screen and seems to lock up the BBPro since the button won't respond and requires a power cycle of the console
    - Choplifter works but has minor graphic glitching with horizonal lines across the top of the image. Seems to play normal otherwise
    - Double Dragon doesn't load up
    - F-18 Loads up but with corrupted graphics on title screen and then locks up after selecting a mission
    - Fatal Run starts up but then locks up to black screen when the demo starts or when trying to start a game
    - Fight Night stars up but the menus have corrupted text and game play graphics
    - Ikari Warriors starts up but with game play graphics corruption
    - Mat Mania Challenge will start but player sprites are corrupted
    - Mean 18 has corrupted game graphics and not really playable
    - Meltdown will give a black screen when trying to load
    - Midnight Mutants gives a black screen when trying to load just like Meltdown
    - Moto Psycho starts but player graphics are corrupted
    - Ninja Golf starts up but main player graphics are missing in the middle of the game play field and graphics corruptions in the map in the lower left
    - Planet Smashers - starts up but sprite graphics are corrupted
    - Rampage won't start, black screen
    - Scrapyard Dog doesn't start, black screen
    - Summer Games is playable but has flickery white lines on the screen only during the opening ceremonies
    - Touchdown Football will start up but then black screen when pressing reset to start the game
    - Winter Games works but has the same glitching horizontal flickering lines during the opening ceremony
    - Xenophobe, doesn't start, black screen
    So that is currently how my testing went last night with the new adapter. One of the main issues I see mainstream with the adapter, is the requirement of an additional reset wire that has to be installed using a clip off pin 13 of the 4013 IC inside the console, and then routed back out so you can plug it into the cartridge adapter. Many of Evie's adapters use and require this so it isn't new or unique to the 7800 adapter. But, I also don't see many folks willing to open up their consoles and remove the RF shielding to attach the wire and then figure out how to route it externally. Nor would they be okay with a wire dangling from their console in order to the use the BBPro. If you never planned to remove it it wouldn't be that big a deal, but then that kills the multi system aspect of having it in the first place. Evie is going to look more into trying to find ways to not require this wire, but in its current state, the adapter and the BBPro won't even load up without it attached.
    So, work to be done with it still for sure and this adapter appears to be a bit more wip still compared to the others I've gotten. But, Evie has always shown strong commitment to supporting her products and in likely short time, she will have quite a few of these issues resolved. I'll be sure to update as she updates the adapter.
  12. CrossBow

    Atari 7800 - Self activating fire buttons?!

    By CrossBow,


    ITC Services Notice
    I received an A1 series 7800 main board in the mail recently where the owner stated it was working properly but was missing a pause button for some reason. Well, when I receive a 7800 system for services, one of the things I do is to pull up a test utility without any controllers plugged in. The reason for this is to ensure that the system controller ports are working properly.
    But you ask... "How does not having any controllers plugged in, help to know if the ports are working properly?" Excellent question!
    You see the TIA controls the trigger functions of the joysticks and depending on the mode the console is loaded up in, the components in use differ a little. But here was the issue with this one that might help explain things a little better...
    The issue was after powering it up without a controller plugged, it the menu selector of the utility kept selecting the first option, exiting, entering...exiting over and over. This behavior was as if the fire button was being held down. But without a controller plugged in?! Quickly using the select and reset buttons on the console I was able to get into the controller test screen and this screen was telling me that not ONLY was the first fire button being pressed, but both fire buttons were showing as being pressed down. It was showing the same behavior on controller port 2 as well. 
    Then I plug in an actual controller and.... it stops auto selecting options and now shows the fire buttons aren't being pressed. Pressing the fire buttons would activate normally. In other words with a controller plugged in, the console seems to work exactly as it should. But that doesn't mean there wasn't a problem here because technically without a controller plugged in, it shouldn't read anything at all. Plugging a controller into port 2, would also remove the condition on port 2 and make everything appear to be fine. So what is going on?
    It turns out that the 7800 is pretty sensitive to the readings it gets from the controller ports and any deviation beyond a certain point will confuse the console. To correct the issue on this 7800 I had to replace at least 2 components and also replaced a 3rd for good measure. The main culprit was unfortunately the TIA chip. Yeap... I replaced the TIA because in most trigger issues the TIA is my first item to blame and usually that is correct, but it didn't solve everything in this case. I did confirm the TIA was faulty using my chip testing as it was showing an immediate fault with the Inputs and audio portions of the chip. Replacing the TIA solved half the issue. Basically controller port 1 was working properly now, but I was still getting errant trigger readings from port 2? This ended up being due to a marginal resistor located at R35. There is a pair of them that control each of the port readings in 2600 mode that each measure 220Ω. The one at R35 was only measuring 217Ω and while that should have been good enough, it was causing odd triggering issues. When I removed R35 from circuit, then the 7800 port 2 buttons were now working properly but of course, no fire button action in 2600 mode testing. So I replaced the resistor with a used one from another 7800 donor board. This replacement measures 221Ω and is much closer to the 220 reading than the original. Installed it, and sure enough everything is working properly again. There is also a 3906 transistor in this mix and it was also replaced out as they are cheap to have on hand and I've a few. But the two main issues were the TIA and this slightly out of spec drifted resistor at R35. Here is a pic of the console where I've outlined the components mentioned.

  13. CrossBow

    Just a simple but kinda cool project?

    By CrossBow,


    Ivory Tower Technical Info & Notes
    The 'Tower' was without power most of last week due to powerful storms on Father's day. As a result it put me behind a bit on console services and projects. Well last night as I've been working kinda constantly on console stuff to try and get caught up, I took a break and decided to do something I'd been meaning to try and implement for a while now.
    I'm sure many of you here are aware of the Atari Vox? In summary it is a small device that plugs into controller port 2 on the 2600 or 7800 systems to allow you to save game scores and can also provide a means for speech to be played back in games that support it. Very cool device but it has one annoying thing about it. That is the fact that the audio from the Avox is separate from the rest of the system so you either have to plug in a set of external speakers or as I had been doing, I would use a 1/8" to RCA cable and plug one of the RCA jacks into one channel (usually the right) on my AV receiver audio input and the 7800 audio out in the other channel. Or, you have to use an external audio mixer to combine the two into one. None of that is really elegant so I thought of a simpler way to go about it. I'm sure you can see where this might be going?
    So the 7800 especially is a little unique in that it was designed to make sure of an external audio input from the cartridge port. Typically POKEY enhanced games use this for audio. The basic mixing for this in the console is to tie the TIA audio coming in internally from the console's TIA chip and the POKEY audio from the external cartridge audio input line with different resistors for each to balance their signal so that one doesn't overpower the other. Well, why not simply add in a third audio line into that mix with a resistor to also bring it down in level?
    That is exactly what I did as is demonstrated in this video...
     
    I have some pics I can provide for those interested but in a nutshell I installed a separate 3.5mm audio jack along the back of this test 7800 I have in the ITC lab and instead of if providing audio output, it is used as an audio input and is part of the mix along with the external audio and internal TIA audio. This allows for all three to be used at once and have all the audio could out through my normal audio output RCAs I have installed on the console. 
    No separate speakers...not Atari audio from just the Left with the AVox speed only on the right. It is all properly mixed together in dual mono as I would prefer. I will next do the same on my actual daily driver 7800 where this would be used most, but I'm glad to have it on my lab 7800 as well. The way this was done, should also be possible on a 2600 and I might very well explore that on a 2600jr I also have in the lab. 
    I know this isn't the first time something like this has been done as I've seen other projects where owners have embedded the AVox completely into their consoles and then with a lot of wiring, use a switch to enable/disable the Avox as needed. But I was looking for a more simpler solution that would still allow the AVox to be used with multiple consoles and not be gutted and dedicated inside a single system and yet still easy to use without a lot of extra wire and mess. One small headphone to headphone patch cable is all that is needed now for this when I want to use my Avox.
    For those that might want to try this on their own, know that a limiting resistor is needed as running the audio output straight in from the AVox is likely to sound messed up/distorted and would cause audio cut off on other audio sources trying to play at the same time. I used an 8k resistor in my test here but I think anything between 6.8k - 10k would suffice. I would also start with your volume pot on the AVox set to about the 1/3 volume level and then play a game that uses both speech and other audio at once to dial in the volume on the Avox until you are happy with it all.
     
  14. CrossBow

    Loctite and ABS = Gallium and Aluminum...

    By CrossBow,


    Ivory Tower Technical Info & Notes
    So over the past few months, I've been trying to find ways of making the RCA jacks that I install into consoles more secure so they don't free spin over time. What I've been doing in the past that actually works 90% of the time far as I know...is that instead of using the small lock ring washer that typically comes with RCA jacks, I use inner star washers of the right diameter to do the same thing, but with more points of contact to lock into the plastic. It also has the advantage of holding the securing nut in place tighter as well since the inner teeth of the washers are present on both sides of the washer. From there, I've used light amounts of epoxy to help hold the securing nuts fast in place as well. 
    This has worked well for years but recently I did have some consoles start to come back where one or more of the RCAs had still somehow managed to work loose over time. So this got me to wondering if there were other methods I could employ. 
    Enter the idea to use Loctite or something similar... Hang tight...there is some history I have to talk about first and a lot of details to follow. Grab a snack and drink and settle in...
    Now there are two types of loctite that you can get for threading applications. One is the red colored stuff and is essentially permanent in that it is very very difficult to remove nuts off their threads if that stuff is used. The other is the blue kind that still allows the parts to be separated (Although not nearly as easily as without...). So I decided to try the blue stuff.
    Now I will say that sure enough the blue loctite holds really well. It basically is a liquid that once exposed to air begins to congeal and turn into a rubber like substance. As a result, it acts as filler between the threads of the nut and the jacks you are securing together. It does still come undone but requires a lot more force to do so and actually squeaks while you remove the parts after it has cured. So it does its job... but... there is also a warning on the package that I did read but didn't think would be an issue in this case.
    The warning says not to use with plastic threaded parts. So I assume this meant not to use it with plastic bolt/nuts sets commonly made of Teflon and the like. Well... I'm here to tell you that isn't the only issue.
    Over a month ago, I installed a UAV into an 800xl. The owner requested I install a separate standard 4pin s-video jack in the opening that the RF modulator used to occupy as the opening is nearly the exact size needed for one style of s-video jacks I have on hand. But they also wanted a pair of RCAs for audio to be installed. They didn't want to purchase an Atari monitor cable specific for this hence the request for separate jacks. So I drilled in the needed holes and got the jacks line up great! To install them, I used a bit of the loctite on the threads of the RCA jacks and proceeded to tighten everything up as normal. I then set the case shell down for about an hour while I recapped the main board and did other things. When I picked up the bottom shell housing I was horrified to see that a long crack had formed between the two RCAs that ran beyond top to bottom of the shell?! I removed the RCAs and discovered that around the holes where the jacks had been installed, there were small spider cracks around the openings and the plastic appeared to be much more brittle than I remembered? So I cleaned everything up and applied some epoxy across the cracks on the inside of the case shell to restrengthen the area and prevent any further cracks from occuring. I let it cure for about 2 days before reinstalling the RCA jacks. This time as they already had the loctite on them, I didn't apply anymore and just had to crank down a bit more to tighten them back up. This time I left them a little more loose than normal and then applied more expoxy over everything to make sure it all held tight. And this worked fine as expected.
    My thinking at that time was that I had simply tightened the nuts on the RCA jacks too much and it caused stress fracturing in the plastic that spread out. Didn't think much of it beyond that.
    Last night while working on a 5200 (A console I've done this work on a LOT of times), I drilled in the holes on the expansion plate as normal using a template I've had for years now. Installed the RCAs and again used some loctite on the threads to secure them nicely in place and then set it aside for about 30min while doing other things. I picked it back up to solder the wiring to it and again was horrified to see a crack had formed vertically between two of the RCA jacks?! I was like, what the heck?! I've done a lot of these 5200s and the expansion plate has never done this before? When I started to remove the RCAs to inspect, the entire thing just started to crumble in my hands like dirt. Sure enough the entire plate had become super brittle and was falling apart in my hands?! At this point I was pretty sure I knew what was happening and decided to test on another piece of similar plastic. Scratched it to expose the inner plastic and applied a little loctite. Yeap... that little piece of plastic became a brittle mess within about 15min of application.
    So.. the lesson here is that Loctite chemically reacts with ABS plastics and causes the ABS to breakdown at a molecular level in a very similar fashion to that of gallium when put in contact with scratched aluminum. Going forward, I'm just going to have to stick with my star lock washers and epoxy it seems...
     
  15. CrossBow
    Seems to be lately that I'm getting in more and more Intellivision consoles that all arrive with the same similar condition. Basically what most might call a black screen when powering on the console but it is more like a dark grey screen with a few lines along the bottom of the screen of even lighter grey. Pressing the reset button does produce a full black screen that will flicker and come back to the same dark grey screen or sometimes it might do something different like an all fuscia colored screen or yellow for instance.
    In all cases, it basically means that some IC chip or component in the chain of the IC logic has failed and the Intellivision isn't able to boot up properly as a result. You can pretty accurately simulate the effect by simply powering on the console with out a cartridge. Same thing will happen when you pull one of the main ICs out of the console.
    But how to troubleshoot it and fix it? Well, honestly the service manual for the model II actually has a decent flowchart but even that still doesn't quite cover everything. So I wanted to share my experience on what I now basically do whenever I encounter this condition:
    - First is to absolutely verify that all the voltages are present to the main logic board. The service manual will have you test the voltages on the power supply board internally sure, but you can have a bad connection on the ribbon cable to the main board causing voltage to not make it to the main board properly.
    - If the voltages check out, then the first actual component to swap out is usually the STIC IC chip (Standard Television Interface Chip). It is one of the several large 40pin ICs that exists in both model 1 and model 2 consoles. Near as I can tell their aren't any differences between the ICs of those two models with the exception that the STIC on the model 1 has a heatsink attached and the model 2s don't. But they can be swapped interchangeably. Although the heatsink on the model 1 STIC will prevent the top case from closing properly on the model 2 console. So you have to be sure the chip is bad as you have to solder it directly to the board for it to all fit.
    - If that fails, then I usually will try and swap out the CPU IC next. Although honestly the CPU seems to be a tank in the Intellivision. 
    - Next up on the model 1 consoles is to look at replacing the pair of 3906 transistors that stand up off the board in the area just above where the CPU sits. Can't really miss it as they get so hot that the board is usually discolored around their solder points. But again, as they get really hot, they do burn out.
    - From here I then grab my frequency counter and verify that I have a proper master clock signal all the way to the cartridge port using Pin 10 to test that signal. Though rare, I have had a crystal that was bad in one and a bad variable capacitor C2 in another that I found by checking the master clock frequency.
    - From here it gets much less straight forward and will require having to break out an O'scope to start looking for various signal waveforms as per the service manual to try and help isolate which component might be at fault. 
    Now in not so common fixes I've done to correct for this same issue.. or corrupted graphics.
    The cartridge port...yeap. The games themselves complete some of the signals in the logic so if a game isn't present or the port has bad connections and isn't making good contact with the game cartridge, you will get the same black screen (dark grey) screen condition
    And I've also had the Hi and Lo graphics rams cause a similar issue although in the cases of those chips going bad, the games will usually load up but look like they are missing sprite data in a way that looks like how NES games look with a bad 72-pin connector where the you have lines of missing graphics or corruption on the screen. Depending on the when the Intellivison was made, it might have a pair of 3539 ICs located in the upper left of the main board with the orientation of the cartridge slot on the center right. They are labeled U7 and U8 on both model 1 and model 2 consoles. At some point a main board design was made and they might have a pair of 2114 ICs there instead. All of the model 2 units have 2114s for the Hi and Lo video RAM and it is located in the lower left portion of the main board on the model 2. 
    So... there you go. A few things to check out in the case of a black screen non-working Intellivision console. I will say that while more complex in components and IC chips, the model 1 units seem to be a bit more robust in regards to operational use vs the model 2. However, the model 2 cleaned up the power delivery quite a bit and tend to usually have a better RF output while being a little simpler on the inside component wise.
     
  16. CrossBow
    Won't got into too many details on this other than to state up front, that I try to be as transparent as possible with the work and services I provide. As a consequence of this, mistakes can and will happen. It is just a matter of when. One such big mistake happen to me this week while installing a very expensive DCDigital setup into a clients Dreamcast. I actually had the main installation done and was ready to test. However, in order for a DC to boot up, it requires that the cooling fan and GDRom drive be installed etc. So you kinda have to put it all back together in order to test an install like this.
    Well I put in a few of the screws in various places to hold things down into place and then proceeded to fire up and test the DC. I got a power light and the controller and VMU beeped. But...nothing else. No drive spin up and nothing on the screen. No signal even being detected. And not just from the new HDMI output but nothing from the analog video side either! I quickly turned it off and tore the console back apart to see what was going on. I removed the DCDigtal setup and tested again. Same thing...nothing.
    It was when I started to do the sniff test to see if anything had burned out that I found it... and what I found horrified me! What did I find? Well...this...

    The picture above shows at least 5 and likely 6 traces between the SH4 CPU and the GPU that were now torn and broken. How? Well notice the pattern of the tears in the traces and how it cuts into the PCB a little?
    Yeap... that was done by a screw. It seems that even though I had carefully laid out the screws so that I knew what went to where, I mixed up the three longer screws used to hold the main board and shielding together along the back of the system, with the three shorter screws used to secure the GDRom in place. And because of that, the screw twisted down into the main board causing the damage you see above.
    The other spot to the left where you see exposed copper is where I was trying to solder small kynar wire to repair these broken traces. But... no luck as the traces are just too small for the wiring I have on hand. And the large ICs on the DC are BGA type meaning Ball Grid Array. They are essentially surface mounted ICs with all of the contact points existing under the chip package so you can't just solder to pins or something on the bottom.
    This required replacing out the main board in this particular case and provided a lesson I'm not likely to forget going forward to always be mindful and double or triple check your work and assembly process. 
    And with that, the owner of this DC will soon be able to play their games again in wonderful HDMI output directly from the dreamcast in the very near future. According to the picture below, the self test fully passed on the replacement main board. The red spots are in fact little hearts that appear when everything is good. You get an X when things fail in the self test.

  17. CrossBow

    Atari 5200 BackBit PRO 4-port Soft Reset notes and modification

    By CrossBow,


    Ivory Tower Technical Info & Notes
    The BackBit Pro multi-system flash cartridge is quite amazing in all the systems it supports and the Atari 5200 is one of the newest systems to recently be added over the past few months. One cool thing that the BBPro cart has for the 5200 side of things that other similar devices do not have, is the ability to reset the console and go back to the game folder browser without having to power cycle the console. This feature works out of the box on the 2-port model 5200s by having a selector switch on the BBPro 5200 adapter set to the 2port Hard Reset mode.

    But on a 4 port 5200, having the switch in that mode will prevent the console from booting up properly. So the switch has to be set to soft reset mode on the 4port. However, even with that switch option selected, the 4port console will NOT work with the reset button on the BBPro cart unless a very small modification is made to the console to allow for this. 
    Changes made to the  2 port main board design and later 4 port consoles allow them to work with the CX-55 adapter and those changes are also what allow the selector switch in the Hard Reset position to actually work and reset the 5200. But the earlier 4 port models do NOT have this ability. That is what I will talk about in this blog as the process to modify the older 4-port consoles to work with the reset switch is very easy to do and doesn't pose an issue with actual games so it can be left in place once done.
    What the modification does is run a new wire to an unused pin on the cartridge port that ties that pin to the reset line on the Antic IC. Turns out that Pin 28 on the cartridge port is perfect for this because that pin was NEVER designed for use with anything on either model of the 5200 and in fact isn't even attached to anything in the system. It is a floating pin on the cartridge port. As a result, it will be given purpose.
    On the 4 port model main board, it turns out that there is an unused via conveniently located near the cartridge port that is already attached to this reset line... NICE! The pic below shows you where this via is in relation to the cartridge port on the top component side of the main board. It is just to the left of the silk screen marking where pin 18 is on the cartridge port.

    And on the bottom side of the PCB, here is where that unused via is in relation to where pin 28 is located on the cartridge port.

    All that is needed is to run a small bit of conductor wire between that via and pin 28 as shown below. No traces have to be cut or anything. Just solder in a wire...simple.

    This attaches a connection from the Antic's reset pin to pin 28 directly so that it can be tapped for use by the BBPro cartridge adapter. As a result, it requires a small jumper pad to be soldered on the BBPro 5200 adapter. On the back side of the adapter, there is a DuPont style female connector attached, but to the right of that and center of the adapter board, is a jumper pad that is labeled as "Spare Reset (Pin 28)". You need to apply a blob of solder across the pads here to complete that jumper as shown in the picture below:

    And that's it! Now you can use the BBPro 5200 adapter on both a 2-port or 4-port console and have the BBPro on cart reset switch work on either model. Just have to move the selector switch to the right position depending on which console model you are using it with. It goes to the left for Hard Reset mode on 2-port and VCS adapter modified 4-port 5200s. Move the switch to the right for the Soft Reset option on 4-port consoles where you have applied the wire modification.
    I'm sure you are wondering what happens if the wire modification isn't done and you have the BBPro 5200 adapter for use with your 4port? Well that is easy to answer. Without the wire modification what happens is that the 4-port console will NOT boot up if the switch on the adapter is in the Hard reset position and it must be in the soft reset position. However, the button on the BBPro will not work properly and just crash the console requiring a complete power off/on to get it back up. Essentially making it operate like other flash cartridges that do NOT have on cart resets. It doesn't harm it to use the BBPro without the wire modification, but it does add just that more functionality to an already excellent product and is a fairly simple modification to perform if you are semi comfortable with a soldering iron.
    Thanks for reading, feel free to ask me any questions should you have any and Atari On!
    -Jesse
    Ivory Tower Collections
  18. CrossBow

    The Ivory Tower 5200 got some TLC

    By CrossBow,


    Service Work Stories
    I originally did most of the work on this 5200 about 8 years ago. It was also one of the first projects I did and to be honest, the wiring work inside wasn't that great. For some time I had wanted to redo it all similar to how I redid my 7800 about a year ago but just never got around to it. Well, now that I have a new BackBit Pro flash cartridge and it was designed to allow resets back to the game menu, I felt it was time to perform a small modification to allow this function of my BackBit Pro to work and also decided it was time to redo the wiring work and give my 5200 a much needed bath.
    So first I will share some old pics of when I first AV upgraded the console. The wiring wasn't that bad I guess but it was before I was using better quality wire and wasn't using connectors so it was all tethered down. Also, not long after this was first done, the s-video jack kept coming loose on me so I had to hot glue it into place. No pics of that hot snot but suffice to say it was pretty ugly. 

     
    Here is another shot showing how all the wiring was done originally in this setup. 

     
    All of the wiring was completely redone with better quality wire and using install methods that I've been using on client consoles for the past 5 years. 

    Some of the wiring was to redo the power and ground wiring as I now have it attached to the main power and ground rails that run along the middle of the board. As a result they are much shorter than they were previously. All the of the video output wiring was redone with a connector added in the middle to allow for easier removal of the main board in the future for servicing if needed. A connector was also added to the power modification wiring on the bottom side as well. 

     
    A new s-video jack was installed as the original was in pretty bad shape from coming loose over the years and the hot glue just had to go. I used my dremel to rough up the area around the s-video jack and shave off a little bit of shell material so that I could install a new s-video jack and have the back nut actually secure it into place properly. Last to ensure it stays put, some epoxy was added around the s-video jack and securing nut. Audio wiring was redone as well and cleaned up.
    Finally a small bit of wire was added on the bottom side of the PCB that attaches the reset line for the system to an unused pin on the cartridge port. The BackBit Pro flash cart is designed to take advantage of this and with this wire in place, I can now use the reset button on the cartridge to take me back to the game selection menu. This is a feature that is sorely missing on the AtariMax carts as they require hard powering the 5200 console to get back to your game menu selection. 

     
    At the end, I finally gave the case shells a much needed bath as it had been at least a decade since this 5200 had been cleaned. It was getting pretty dusty in those vent slots and just looking a bit dull. Now this 5200 is working better than before and ready to provide some more 5200 gaming for many more years!

  19. CrossBow

    5200 with very odd keypad / fire button issues

    By CrossBow,


    Service Work Stories
    I've done a video on something similar to this but here is a rundown on what I was encountering:
    A 5200 sent in for services had a note stating that top fire button wouldn't work on the console. This is an issue I've run into before and in fact have created a video on it. It can be due to the controller having a broken trace of course on the flex circuit inside it. But... it can also very well be due to a faulty 4052 MUX chip inside the console located at U13 or A13 depending on the age of when your 5200 was made.
    Well, that was indeed the same issue with this 5200. But after replacing that and confirming the top fire button was now functional again, I then used my port loopback tester board with the diagnostics and was surprised when a slew of other errors came across indicating issues with the keypad. 
    I then used a different program for just testing the controllers and sure enough, whenever you put a controller into port 2 and pressed the pause button, it would call the entire aux buttons to register all at once on both controller 2 and port 1 even though a controller wasn't plugged into port 1?! So that meant Start, Pause, and Reset were all registering at the same time. I later found out that when pressing the 4,5, or 6 buttons that it would also register ever single keypad button in that same column to also register. Obviously that wasn't going to do!
    In testing the other ports, I found out that port 4 suffered similar issues but only the keypad section was messed up in that pressing 1,2, or 3 would cause all the keys on those columns to register at once. Very odd.
    Diagnostics told me it was a keypad issue so that was good. I then went to the service manual proceeded to follow the flowcharts for what might be the issue. My 'hunch' was that one more of the other 4052s was having issues. However, the flowchart kept pointing me to either a faulty GTIA (Which does handle some of the keypad controls), bad GTIA socket, or a bad 7400 chip near the RAM section. So I tried replacements GTIAs and 74ls00 chips with no change. The flowcharts have you using an O'scope to check for activity on the various triggers lines and such. Well, I was seeing activity or pulsed indicating polling that the console is doing to check for buttons being pressed, but I was seeing something else odd as well. I was seeing what would appear to be ghost pulses between the normal square wave I should be seeing.
    I proceeded to then use my multi-meter and checked all of the connection points from the GTIA to the passive components to the MUX chips to the controller ports looking for any shorts or broken traces. Everything was checking out... After hours of checking everything the flowcharts and schematics were telling me and nothing else to go on, I decided to something I should have done in the first place. Guess what that was?
    I removed each of the 4052 MUX chips (Kinda a PITA since these were all soldered to the board and not in sockets). And checked each one of them in my Bitback chip tester pro. Sure enough, I found another failed 4052 at position U12 about middle of the board just ahead of the controller ports. After installing all new sockets and putting in the original 4052s that passed and replacing U12. Finally the controllers were working proplery again and the controller loop board was passing the diagnostics!
    The moral here is that people are SO quick to blame the controllers on the 5200 for their woes. The reality, is that the 4052 MUX chips are very prone to ESD failure and fail they do...often. Especially the RCA branded ones.
    Next time you have controllers issue with your 5200. Don't just assume that controller is a POS and blanket blame it. Have the console checked out to be sure it isn't something internal causing an issue.
    The pic below shows the two 4052 MUX chips I had to replace to get this fully working again. They have little silver dots on them to indicate I replaced them and to make where pin 1 is. Again, they are highly prone to failure so if you own a 5200, best to have a full set of these on hand just in case. They are cheap ICs so it is good insurance to have on hand. In this case I have small stash of OEM RCA ones that have tested good that I've pulled from other dead 5200s over the years. I suspect in the past that U10's 4052 was changed out in the past as it was already in a socket and had a different lot number on it from the others. 

  20. CrossBow

    Not all consoles are stock that I work on...

    By CrossBow,


    Service Work Stories
    As part of a large project I've been working on for over a month now, one of the situations I encounter is when a console is sent in for services that has already had another tech's hands inside it. In most cases, it might be simple repairs like replacing an IC chip or some capacitors. But now and again, I get a console sent to me that I don't always know what to expect. In those cases, there can be undesired surprises waiting for me. Here is a 2600 that I would like to show as an example of what I'm talking about.

     
    I don't know whom originally did this work. But I will sum up what you are looking at. It appears this console was previously upgraded using one of the Low Budget AV upgrade boards for the 2600. I've not seen the results of this board in action myself and in fact this one arrived in non working condition with video sync issues and obvious missing colors on the screen. What you can't see and I should have taken a picture of, is that the wiring on the AV board in the bottom of the picture above that is nearest to the main board, actually attaches to pins off the TIA chip. However a few of these wires had broken loose from their solder joints on the TIA pins.

    The pins were pulled out of the socket and then soldered to the legs. However, some of the connections had broken loose because honestly, network twisted pair wire isn't that great for point to point solder work and doesn't take solder that well. But this meant I had to remove the wiring completely (Was going to anyway), and clean and reset the pins on the TIA. The original socket was also pretty messed up with some melt marks on it and even some solder that had dropped into the socket in a few places. The socket was replaced and the TIA seated back in once the legs were carefully put back into position and cleaned up. Here is how the TIA looks now. It is the large bottom IC in this pic.

     
    It was also semi messy near the AV output jacks. I'm reusing the jacks in this project, but removed all of the wiring and most of the hot glue that had been used to try and keep everything more secured. Here is what that looked like.

     
    I've already removed the hot glue that was scattered about on the jacks and removed all of this wiring. The AV jacks will be removed minus the s-video 4-pin on the right there and star lock washers added to ensure a snug and tight fit. All new wiring will be ran to these jacks and routed back to the newly installed UAV that is replacing the original AV board setup. Here is the UAV in place and burn in testing being done using temporary wire harnesses that made up years ago.

     
    This 2600 should be finished up later this evening. I will try and update with a picture of the new wiring in place once it is fully completed.
     
  21. CrossBow

    A 7800 that would only play 7800 games...?

    By CrossBow,


    Service Work Stories
    I'm not going to provide a ton of pics on this one because it just isn't needed. But I had been fighting with a 7800 that I've been servicing for a total of just over 12 hours in trying to figure out why it would only play 7800 games? If you put in a 2600 game, it would only give a black screen and not much else. If I put in my Plus+ cart, I could barely make out the plus cart logo on the screen as it would flicker all over.

    This told me that the 7800 was in fact switching over to 2600 mode properly or at least would appear to be in order for the plus cart to start loading up. But as you can see the picture is not correct and what you can't see in this static photo is that the image would only blink in and out quickly for me to see this. It took some doing to capture this frame on my PVM to show it.
    I first replaced some of the 3906 transistors that sit above the MARIA IC chip as I had one in the past with a similar issue and one of those had been the culprit. In the end, I ended up replacing all of the transistors on this board along with trying alternate ICs from my working test spares to isolate the issue. Nothing worked and I was about to toss in the towel and tell the owner that it would forever have to be a 7800 only console. 
    Then in checking some traces (suspecting a bad trace somewhere), I happened to touch my meter probes to two of the pins on the cartridge port and was surprised when the metered 'beeped' at me?! None of those cartridge pin fingers should be touching unless a cartridge inserted is causing a connection to do so. In looking further, I could see a dull looking color in the bottom of the far left side of the 7800 cartridge slot. I thought it was paint because it was so flat and kinda dirty looking. I cleaned and cleaned with 99% IPA and contact cleaner and whatever it was just would not clean out of the slot. Eventually I use a sharp larger end of my soldering boring tool to poke and scrape and it came loose. After some mangling with my tweezers I managed to pull this out of the cartridge slot...

    It looks like a blob of solder, but in fact it is foil tape?! It is very similar to the tape used on the 2600 switches from Atari as part of the ESD protective measures. It is all twisted up here because of my scraping on it with my tool and using the tweezers to pull it out. But yes, this little bit of foil tape had gotten into the slot at some point in time (Prior to it being send to me), and was the issue. Removing it, removed the short on the cartridge pins and 2600 games now come up and work properly again.
    The reason 7800 games would work, is because when you inserted a 7800 cartridge into the slot, it would push the pins back enough to NOT make contact with the foil tape. But with out a 7800 cartridge inserted, the pins were all grounding out. This was confusing the 7800 and so it wasn't really switching fully to 2600 mode as it should have been. Basically, it was running 2600 code in 7800 mode so the clock signals were all out of whack as a result. This is why the video output was all goofed up.
    So the lesson here, is that you always need to check power first when encountering issues with a console, but be sure to look into the cartridge slots for any foreign debris as well.
    BTW... when the console first arrived to me, this is what I found inside. It came to me in power on but otherwise non working condition. I wonder why?

  22. CrossBow

    Quick update on the ITC

    By CrossBow,


    Service Work Stories
    Just wanted to give those that might be curious, an idea on part of what my project has been lately that has taken up much of my time as of late. These photos show 13 different 2600s that I recently serviced and installed UAVs into along with all the needed AV jacks installed as required by the client.

    An no...these do NOT have two sets of audio outputs. The red/white on the left rear next to the 4-pin s-video mini din, is actually separate chroma/luma connections. This is handy for connecting to older monitors that only had RCA jacks for s-video connections. The yellow & white/red on the right rear are the composite and dual mono audio outputs. I figured the easiest way to keep it separated given the RCA colors I can get, would have been to keep the s-video all one side and the rest to the other.

    Most of these consoles are revision 13 with a few 12s, 14, and even one revision 16 in there. UAVs install pretty much in the same manner regardless of revision with the only difference being a few changes on where some of the video signals are tapped from due to changes in the PCB trace designs. 
    Last is a pic of 1 of a few 7800s that are also part of this project. The first 7800 is essentially done minus the av jacks and wiring for it. But this is essentially what a 'works' upgraded 7800 from the ITC looks like these days. It has new front panel switches, new capacitors, a new dc-dc switching regulator in place of the linear voltage regulator, a Kiloparsec BIOS upgrade, and a UAV installed on top of one of my mount boards I designed a few months back. 



  23. CrossBow

    Installing a UAV into a heavy sixer

    By CrossBow,


    Service Work Stories
    The process to install the UAV into a heavy or light sixer is pretty well known and documented. In summary you basically set the jumpers on the UAV for the 2600 setup and then solder a socket ontop of the 4050 IC chip and header pins into the UAV and plug it into the socket. Job done... 
    However, there is a caveat to this method that doesn't become apparently until you find yourself moving consoles around a lot. And when I mean moving the consoles, I mean as in them being packed up, stacked up, put away into storage, shipped about...etc. Or let us say...for convention use. What happens is that all the jostling and movement of the console overtime will cause the UAV to walk about of the socket and come loose. Once this happens, the socket is essentially worn out and it will have more often. The solution is to direct wire solder in the UAV to alternate points and then affix the UAV in a way that isn't as likely to come loose over time.
    The solution I came up with recently, was to use the empty space on the PCB where originally Atari had planned to install a built in game on the console. There is space and markings where a 4k ROM would have been installed on the sixer PCBs for this purpose that was never used. So that provides a nice flat area to attach the UAV with double adhesive tape or what I use which, is 3M Dual Lock fasteners. Basically plastic industrial grade velcro like reels that can hold up to 10LBs of weights supposedly before coming separated. More then enough for a little ole UAV. The adhesive that is used on the Dual Lock stuff is also crazy strong if you clean the surface well before hand. To attach to the UAV is trickier because the UAV doesn't have a smooth surface on it that is really large enough. This is due to the UAV having components installed on both sides of the PCB, plus the wiring etc that is also needed. To help get around this, I've been buying 3/4" shrink tubing that I can get very cheaply locally and sliding it over the UAV after my initial wiring to it is done to provide me with a much smoother and consistent surface area for the other dual lock velcro to attach to. This install required the use of the basic version of the UAV that doesn't require jumpers to be set as it is all direct wire.
    The wiring on the sixer might not be consistent across the heavy and light as I only had this heavy on hand currently. But it turns out that 4 of the 5 connections needed for the UAV can actually be wired and soldered to empty unused vias on the main board. Even better, is that these alternate vias (I think they were test points), are very close to where the UAV sits and provides some pretty direct runs keeping everything nice and tidy. The pic below shows three unused vias right in a line above the disc capacitor marked as C210 on the board. From left to right these vias connect to TIA pins 2,7, and 8. If you look at C210, you will see an unused solder pad directly right of it. It is between the markings for C210 and R208. That is where you can tap audio from as it is directly connected to pins 12 & 13 off the TIA. You will see another unused via just off to the side of R214 below. That connects directly to TIA pin 5. Finally, you need a connection for the TIA color signal. That can be had easily from soldering a wire to the right leg of R212 as oriented in this picture below.

    Now, something to keep in mind is that on these older 2600s and on later 4 switchers, (possibly the jrs?). Atari would add in an 800ish  Ω resistor to help with color saturation. However, this resistor will cause the colors to look way off in most cases through the UAV and has to be removed from the circuit. It is located essentially between the pin 6 and 9 positions below the TIA chip on the main board at location R213. What I usually do is to just de-solder and lift the right leg of this resistor as that is also tied directly to pin 9 of the TIA. So you could use this solder pad for the color signal as well but it would require a longer wire to route down there.

    Power and ground can be had from several places. I ended up using one of the unused vias for the non-existent 4k ROM for ground. Power was possible from here also, but would have been in the way of my UAV board installing nice so I took the +5v off the bottom leg of R207 just left of where I placed the UAV. Again these points were chosen to keep all wiring to short runs. Shorter wires help with minimizing signal loss and keeping the UAV board in place over time.
    And that is pretty much it. I should also mention that if wire length isn't a concern, then with the exception of audio and the power and ground connections, all of the other points mentioned can also be tapped from the resistor legs mounted below the TIA. I don't recall which is which right now, but I know that all of the TIA connections can be had from them also. Just requires longer wires to route around the TIA to those resistors. It is also possible to mount the UAV on the bottom of the pcb using strong double adhesive tape and then just solder the wires directly to the legs of the TIA. But you would have to make sure you are using the basic version of the UAVs for such an install and it would require likely drilling a hole on the side of the RF housing box for your output wires to come through. You will see in the overview pic below of the UAV installed, that my output wires go under the cartridge slot and out the back. That is because the housing has some thin slot openings on the top and bottom allowing wiring to come through. It might require having to file the metal down a bit to opening the gap but might not require it depending on how the housing for the 2600 was done.

     
    I might create an install video that essentially tries to cover UAV installs in the sixers and 4 switch units in the future as a single all in one video. While solder points are varied across the different revisions of the console, there is enough similarity that I think a single install video with pauses and different sections for the different revisions is possible. Have to think about that...
     
  24. CrossBow
    I bought this kit a few months back as a pre-order and had to wait since I wanted a different colored shell. But the kit allows you to use a donor GBA mainboard from a standard GBA and essentially turn it into a small console to play your games on a modern big screen display using an SNES controller. Here are thoughts on this:
    The small ribbon cable that has to be soldered to the GBA CPU is tricky and requires a lot of patience to get soldered into place. The pitch of the soldering is quite fine and I had to use my 10x loupe to verify the connections and check for and remove any bridges I found (There were quite a few). The ribbon cable is designed and marked to help you line everything up. It has a nice center GND you solder down at the corner of the CPU to help anchor the ribbon in place. There are also markings showing where pin 1 and pin 127 should be lined up. However, the first time I tried this, I actually had the left hand side of the ribbon where pin 127 is one pin off. Due to the way this ribbon is designed it is possible to have one side perfectly lined up but the other side be too high or too low allowing for a 1 pin offset as I had initially. No damage done as it just meant my controls weren't working initially. But it did require me to carefully undo and remove the ribbon completely so I could clean up everything, re-align it and do it again. This picture below is of the final and successful placement of the ribbon on the CPU.

     
    The kit comes with a 3d printed case shell. You can choose from the colors they already have on hand and available if you are in a hurry or you can specify the color you want. I do have to complain about this part because they don't list all the colors in their order page and only stated that with a custom color, you specify. However, there isn't a comment section or anything in which to specify this?! What I did and apparently this worked, was when I made my payment via PayPal for the kit, I specified that I waned a purple case shell if possible otherwise red would be good. But again, they didn't have a list of the colors they can do anywhere so I was guessing they could accommodate my choice. They did as do have a purple case shell for my kit. The fitment of the case was great as it initially arrives already pieced together without the screws in its own bag. However, once everything was assembled I found quite a few issues. For one, the GBA mainboard doesn't line up flush with the edges of the case shell so everything is recessed inward about a 1mm or so. This isn't a huge problem, but it doesn't look as finished as it could. The holes on the inside for screwing everything down into place doesn't allow for any adjustment so it is what it is. I also found that the openings for the ports on the back are a tad on the too small side of things. But since it doesn't sit flush anyway, this doesn't matter that much. It did come with two power buttons I can choose from. A grey solid printed button, or a white semi translucent one. I chose the white hoping it would allow the LED on the GBHD board to shine through. Spoiler...it doesn't.
     
    However, the main GBHD FPGA board does seem to sit more flush with the front side of the case so there is that.

     
    The sticker comes in the kit and is an optional thing you can apply. I sprayed off the top of the case with some 99% IPA to make sure it was a clean surface before applying the sticker on mine. I think I got it lined up pretty well for eyeballing it.
    So...what about the output and overall thoughts?
    To sum up...it is outstanding! The way the kit works is that the GBA main board is only used to provide the logic for reading the game and handling the controls. The LCD driver on the GBA main board is what is providing the video output to the GBHD FPGA board that provides the final output. As a result, you remove the battery terminals and the speaker off the GBA main board as they are NOT needed and take up additional space. In fact, on some of the other GBA console kits, you have to make sure to put the GBA power switch in the on position, but because of the way this kit work, it is providing voltage directly to the CPU when you power it on. As such, the power switch and volume wheel have no use or function anymore since all of that is bypassed. In fact, the audio comes straight off the CPU pins and is handled by the GBHD board itself. In a nutshell the GBHD FPGA board is really doing the heavy lifting for the video/audio output and as the interface for the controller input on the front. Audio is an issue for some as I've been told it isn't compatible with all setups. This is because the audio appears to be handled as PCM analog through the HDMI and I guess newer TVs and AV receivers don't support that? My AV receiver in the game room is 10 years old and not only does it support PCM audio, but supports up to 96khz PCM so I had NO issues with this on my AV setup.
    Once installed, the kit allows you to pull up a simple to use OSD for changing a few things on the video display. It defaults to output at 720p and this is really the most compatible and best looking option as it provides about a 4x scaling from the GBAs original resolution. It has different modes to control the aspect of the image from proper integer scaling (Default) to stretching to fit your widescreen or a setting of in between with a little stretching and some minor borders around the edge. It has an option to compensate for overscan and this was needed on my TV in the lab area but not required on my main TV in the game room. You can also choose what color you want the border to be if you so desire. There are options for LCD grid like effects and scanlines. These look okay but I'm not a fan of either when playing on my big screens. There is also some filters but I honestly think they made the output look worse on my modern TVs. My guess is they are there to help provide a better look if you use this with other equipment to play on a CRT but that is just a guess. My kit came with Firmware v4 pre-loaded and apparently was assembled back in June of this 2022. I do see via where something like a jtag header could be soldered in but do NOT see or know of a way to update the firmware in the future. It might be possible this is something that could be implemented in the future using flash carts? But that is only speculation.
    How does it look? Well here is a quick 1min video of it in action with the game Iridion II since I had that handy for testing. I used my phone to get this so it isn't direct capture but you get the idea.
     
  25. CrossBow
    So as the title states, I'm temporarily suspending my console services for repairs, refurbs, and upgrades until about the fall timeframe. This is to ensure I have plenty of time to work on a large project that has a strict timeline. Anyone that has already sent their systems to me will still receive their service requests and will take priority to get them done quickly. But for others, I'd rather hold off and have them wait because I'm not comfortable with my client's systems sitting at the ITC for what could be a few months.
    I do apologize for those that might have been holding off and wanting services done, but rest assured I will be able to provide services again in a few months to the general public. Thank you for your understanding and if you have any questions, do feel free to contact me.
    -J. Hardesty
    Ivory Tower Collections
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