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CrossBow

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  1. CrossBow
    Here is an issue that I've seen before in one form or another and I thought I would talk about it here while working on a earlier era 2600 heavy sixer last night. The system was sent in for refurbishment. In this case that is all the original electrolytic capacitors being replaced out, new DC power jack, new voltage regulator etc. But a problem was reported and confirmed during testing of the console.
    What was the issue? In this case it was an issue with the player 2 controls. Specifically, player 2's fire button was always registering as being pressed. Easiest game to demonstrate this was Air-Sea Battle as when you reset the game to start, player 2 is constantly shooting the entire time even without a controller plugged in. Part of the refurbishment process is changing some components near the joystick port per an Atari service bulletin from back in the day for ESD protection.
    It is the last part in regards to the ESD protection that needs focus, because it was found that static electricity from players hands when inserting and unplugging the joysticks, would cause static discharge to the joystick pins. Luckily for most this is pretty harmless but one component in particular on the heavy sixers is very sensitive to this and prompted Atari to create the service bulletin to address it.
    The specific component to be checked is labeled as A203 on the main board. While the original IC chip has an Atari PN labeled on it, the chip is a bog standard 4050 IC that was common on the 8-bit line, 5200, some 2600s and lots of other devices. So common in fact, that the 4050s are still made today. However, on the heavy sixers, the trigger lines (Fire button) goes through the 4050 chip and in turn relayed back to the TIA. The most basic way it works is that +5v is always present on pin 6 of the joystick port which is the trigger line for each controller. When you press the fire button, you ground this connection causing the +5 to drop to near 0. This is what is referred to as going from Hi to Lo and is how the system knows when controller inputs are being used. In the case of this 2600, pin 6 from joystick port 2 was not showing any voltage from it and as a result, this was being interpreted by the logic in the system as if the fire button was already being pressed down. The basic troubleshoot process here is to verify the traces from pin 6 back to pin 7 on the 4050 IC chip and ensure there are no broken traces. If that checks out, then the culprit is down to two component at that point being The 4050 IC or the TIA itself. 
    Anyway, per the service manual flow charts and because I found no issues with the traces on the board, I removed the original 4050 IC chip, installed a socket and new 4050. Let it burn in test for several hours last night and verified that player 2 is now behaving properly and not so short tempered.
    So in this case it was an easy fix but also a warning on why ESD was and still is an issue to this day. In this case, an errant spark from someones hand in the past damaged something internally in the 4050 IC causing it to no longer function properly in regards to the player 2 fire button.
    Replacement 4050 IC installed in new socket however, I did eventually replace this 4050 out also with a new Ti branded one as this on would cause graphic visual issues after a while.
     

     
    Just a pic showing the soldering work after installing the new socket and 4050 IC chip.
     

     
    Here is one of the new cap+diode component fixes applied to port 2 at location C237 as stated in the Atari service bulletins. There is another component set like this on the player 1 port C236 location as well.

     
  2. 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. 
  3. 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.
     
  4. CrossBow
    This might require its own thread but I actually was working on an NTSC 7800 that was eating my lunch most of the weekend. It was sent in for just a basic composite mod installed into it. When I used the diagnostic roms everything was fine with this 7800. But then not long after I got the composite board installed and tested it again, I noticed some odd flashing lines of colors across the screen. It seemed to do this badly on Dungeon Stalker and Ballblazer. In the case of both games, it would flicker around with the color like this for anywhere from a few minutes to about 10min and then just abruptly lock up or got to a black screen?! It was also doing it through the RF when I put everything back in stock condition and reinstalled the original components I had removed. I replaced every single one of the main ICs without any luck starting with the Maria as it wasn't doing this in 2600 games. I did try to install my cap off the A15 line in a similar fashion as my other video I did about this,  but that didn't change anything either. You know what removed 90% of the flickering color bars on the screen and stopped it from locking up?
     
    The freaking crystal! (Y1) I removed the one in it and replaced it from one of my 2 parts donor 7800 boards. The first one I popped in the flashing colors were only occasional on the game ballblazer but didn't happen at all with dungeon stalker or any other games I tried. And more importantly, it didn't lock up either and BB and Dungeon Stalker both ran for several hours before I finally shut them off. I did try other crystals to see if I could get the slight flicker to go away completely but that only took it back to the way it was. So obviously something in the crystal I installed from the other 7800 seem to mesh better with this 7800. I also replaced every single one of the 3904s starting with Q3 and Q4 as both of those were installed. In fact this 7800 was kinda strange. Seem to use a later revision board, had C64 for the extra timing circuit on it, but was missing the rest of the ICs you usually find in that circuit? It also had all of the caps and resistors installed, whereas most of them show some removed at the factory by clipping them out or just not being installed in the first place. It also was using Sony 10ns speed RAM in it but no resistor installed on the bottom RAM chip as I normally see with most of the Sony RAMs. (BTW replacing RAM didn't do anything and in fact just gave me a black screen).
     
    So all I can say is that timing on the 7800 doesn't have much room for tolerance it seems and that all of the components we find installed into the consoles was done so at the factory in what seems like a case by case basis? 
     
    BTW when I put it all back together and replaced all the RF shielding, the flickering seemed to go away completely at that point? I'm still not 100% sure it is 'fixed' but it is a strange issue for sure and one I hadn't yet come across.
     
     
    View the full article
  5. 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.
     
  6. 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.
     
  7. 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. 



  8. CrossBow
    As some might know by now, I've got an MT-200 that I picked up over a month ago now. Really cool little device from Roland that was originally intended for use in teaching music. But these devices have the ability to play back midi files through built in disk drives that use IBM formatted 3.5 inch disks. They can also be used as sound modules and with modern day computers can still be made to be used with ScummVM and Dosbox for classic gaming. Anyway I was getting frustrated with my disks seeming to work one day and then a week later suddenly given me read errors. So I read up on using one of these cheap Gotek floppy emulators into mine. But information on actually making one work with my MT-200 wasn't to be found. I did find Gotek's pre-configured to work with devices like my Roland MT-200 and its variants on eBay, but at $80 + shipping that seemed crazy to me. So I bought a generic Gotek with the intention of figuring out how to make it work in my Roland MT-200.

    I was quite successful and it turned out to be MUCH easier than I thought it would be. I did a video last week on the process of which jumpers are needed, the installation, and the software I found to make it all work in my Roland MT-200. I now share this knowledge in my recently released YT video so that you don't have to pay those crazy prices on eBay either and can hopefully find this useful:


    View the full article
  9. 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).
     
  10. CrossBow

    The curse of the Saturn horizontal lines!

    By CrossBow,


    Service Work Stories
    This story starts a few years ago when I powered on my model 1 Sega Saturn and played a game for a bit and then powered the console off and back on to switch to a different game. But to my horror I discovered some strange horizontal white lines scrolling upwards on the screen? I powered the console off/on again and the lines were still there only now there were a lot more of them and they were scrolling much faster. Additional power off/on cycles would only cause the lines to change thickness and motion and scrolling rate. I don't have a picture of my actual console doing this, but here is one on youtube that demonstrates the issue very well. It is best to see it in motion anyway to get an idea of how annoying it really is..
     
    Reading up on the issue you find a few different fixes for the issue or no fixes at all. The most common fix thought to correct it, is to replace the caps in the PSU board. Saturn consoles have their PSUs internal inside them. Luckily they are all throug hole caps to not that big a deal to replace. But you have to make sure when ordering a cap kit, that you order the right one for your Saturn as it seems there over a half dozen different PSUs used on the various Saturn models and they all have different component layouts, different amount of caps needed, and of course different values of caps used. So that was the first thing I did was to recap my PSU. And at first I thought things were good... but nope. The issue would happen after about 10min of playing a game and when powering cycling the console again to change games, the white lines would be back?! Keep in mind the actual console continues to play normally but visually it is less than ideal.
    The next common fix for this issue that has worked for a few people, is to replace the main PWM switcher that is on the PSU boards. There were two main types used in the Saturns depending on the country it was being used in. For instance in Japan and NA. The PWM could handle between 100 - 120v. In Europe it was for their 220-240v ranges. The exact PWMs used are difficult to find but I did some sleuthing on this over a year ago and found a modern drop in replacement that can be used in all regions as it can handle between 100 - 240v by itself. These can be purchased from console5 if needed here:
    https://console5.com/store/top224yn-saturn-power-supply-pwm-75w-voltage-regulator-replacement-for-top102yai.html
    But sadly once again in my case, it was not to be the fix for mine. So I've just kinda lived with the issue now. Until last night when I remembered something and then tested it a bit.
    Remember when I said that powering off/on would cause the lines to be different each time on my console? Well, I also discovered that if I could quickly turn the console off/on enough to cause the screen to dim for a sec but not enough to cause the saturn or the game to actually shut off, that sometimes those lines would go away?! That got me to thinking... which, in all honesty can be a bad idea for me sometimes.
    The power switch changes the conditions depending on how quickly I'm actuating it. Or maybe the force used to power it on and off? So...
    I decided to take the switch apart. This was NOT an easy task. The switches used on these earlier model 1 units I believe are different than later made models. It has an additional power protection component soldered onto the AC input wires on the side of the switch. Wrapped with a bit of yellow electrical tape, and then a blue/green translucent colored rubber cap that was draped over it to protect everything. Once you carefully remove all of this (As you will want to reuse at least the rubber cap). Then you have to pry apart the steel housing that covers the top portion of the switch. Once you have done this, you have to be careful of 2 things. Both of which are springs that will do what springs do best. They will likely shoot out somewhere and you won't find them again if you aren't careful. My wife may or may not have a non functioning ball point pin in her pen holder as I type this...
    Once I got this figured out and was able to study the switch. I then found old yellowed colored grease inside the switch along with a bit of black carbon residue mixed into the grease. Similar to what we see on colecovision and atari toggle switches. I cleaned all of this gunk out and put it back together with some new dielectric grease. Once I got that switch back together. I crossed my fingers and turned on the Saturn. No white lines! But I couldn't get excited about it just yet because what I didn't mention is that most of the time on the first power on, the Saturn doesn't have those lines. It is only after it has been on for a bit and then I power cycle it that the lines would appear. So I played some Bulk Slash and got through a few missions and powered the console off to switch games. Turned it back on... and still no white lines?! This is a good sign. I continued to play several different games for at least another hour and half power cycling the console well over a dozen times in the process and those pesky white lines have not come back.
    So it would seem that power switches are another potential source for the white lines issue on Saturn consoles. I'm not sure why the first power on would always be good and it was only successive power on attempts after that would cause this, but for now it seems those issues might finally be corrected. I will have to play a bit more Saturn games to find out. What a chore... 😉 hehe.
    Here are some pics of the insides of my Saturn for those that might be curious. I recapped the entire thing several years ago and at the time only radial caps were in the kits so I had to install them in a similar manner to how it is done on Gamegears when replacing surface mount like caps with through hole radial type. And, it has a Hi-Saturn region free BIOS installed as well. Even with the Rhea configured to report every game as being NA/US, the Japanese games still wouldn't load right and would require me to use my Acton Replay cart to bypass. But as that cart becomes more and more finicky to use, I opted to just install the region free since in this model Saturn, it is literally a drop in replacement chip.

     

     

  11. 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!

  12. CrossBow
    This one was quite tricky and I'm still not 100% convinced this was the full cause. However, grab a snack and a drink cause here we go...
    An older 2600 heavy sixer was sent for just a refurbishment and no upgrades. Basically just replacing out the components that come in a standard console5 refurb kit. But I immediately knew someone was off about this console before I even opened it up due the bulging I could see in the front facia switch section near the left side of the cartridge port?

     
    Upon opening it up I also found that whomever was inside this previously (and I know someone was), had also applied some very sticky foil tape around the RF modulator housing? I think this was done to improve the picture output as this H6 does have pretty poor RF output compared to most I've worked on.


     
    I actually removed this foil tape completely. Took the RF modulator from off the switch board and disassembled it. I then removed and applied new solder to all components on the RF board as much of the solder was looking pretty old and I could see what looked like old joints with some possible hairline cracks starting to form. This along with the refurb kit has improved the RF output a little but not as much as I've seen in the past. I suspect the RF modulator itself has some other issue going on but as it is the 3pin version, they aren't that common for replacements. Also the tuning coil in these appears to be locked in place as this one just didn't want to move and I didn't want to chance cracking the core trying to force it. So it is stuck in the position it was given from the factory around the channel 3 area. Some of my TVs did have issues locking onto this console's signal but of course the CRT downstairs had no problem with it.

     
    So what about the power issue that this Blog is titled for? Well, after doing all of this, the console still had a strange issue where sometimes when powered on, I would just get a blinking screen of snow and black...snow....black...snow...black. Something I hadn't seen before. Since you always ASAP electronics issues I first checked the input power which was given me a steady 13.2v on the input side. This would drop to about 12.4v when the console was powered on which, is to be expected for the additional load once the rest of the circuit is active. 
    It was when I checked my voltages on the new voltage regulator that was also installed that I found something very odd! I was getting a 12.3v reading on the input pin of the VR which, again is quite normal, but what wasn't normal was that the output pin of the VR was showing 11v ?! It was then, using my meter that I found that somewhere the input and output pins of the VR were shorted. How this console worked in the past is beyond me because 11v off the output pin of the VR would also be getting sent to the mainboard in the metal housing and that can't be good! In looking at the old schemes for these boards the only spot I could see that might cause this was taken up by this rather large guy here:

    That is a 2w Allen Bradley style resistor. According to band colors, this is a 68Ω 5% resistor. I took it out of circuit and sure enough the short I was getting between the input and output pins of the VR went away. But the resistor was reading 71 - 72Ω which is within the 5% tolerance spec. But taking a chance I powered on the system without it and it came right up and appeared to be working just fine. I then left the system running moon patrol for about 8 hours yesterday to make sure everything was good. And it was fine. 
    My understanding is that this resistor was added to reduce the current on the input going into the VR so it wouldn't get crazy hot. But the VR was replaced and I drilled a hole into the heatsink so I could use a screw and nut to secure the heatsink to the VR vs the clips that were used on these originally along with new thermal paste. That 8hour session of moon patrol did get the heatsink warm but not enough to burn as I could keep my fingers around it without it getting too hot for me to touch. So perhaps the older VRs couldn't dissipate the heat as well and this is why these large resistors are only present on the very early model H6 units. It might even be the first one I've seen that has one as most of the others I've worked on I don't recall seeing it present. 
    Anyway, I'm going to power on and test this system again today to be sure it is still working properly but hopefully it is good to go, and ready to go back to its owner.

     
  13. 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.
     
  14. 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.

  15. 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...
     
     
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