The great 7800 UAV mounting project.

[CrossBow]

I've spoken about this in a blog previously and even updated the blog to show the actual PCB and sample of it installed. While I did make a very tiny error in my trace layout design, it isn't huge and is something that can be fixed in situ when I'm putting these mount boards together. So..what is this all about?

For sometime now I've been wondering about different ways to install the UAV into 7800 systems that might make it easier and look more professional as a result. Several ideas came to my mind and I also knew of at least one other person working on something similar. But as they hadn't made any progress towards it and eventually got out of the modding business, I decided a few months ago to look into this again.

The UAV is an amazing upgrade board. But as it was mainly designed around the Atari 8-bit computer line originally, the UAV design and installation are simpler on the 8-bit computers and 5200 as a result. But for several 2600 system revisions and the 7800 installs, wiring and quite a bit of it is needed to have a working UAV. But in the case of the 7800, most of those needed wire connections are actually all along a straight line in one portion of the 7800 main board. So it seemed that something should be possible to come up with an easier way to install the UAV. Additionally, if I'm to design something, then perhaps it could also be designed so that some other ideas could be added for consistency and to correct for some deficiencies in the UAV in regards to 7800 use.

That leads us finally to these:

 

 

Above is a pair of ready made mount boards. The board is designed so that it sits above the resistor ladder section and provides fairly easy to solder board interconnect pins that solder to the resistor legs directly. In addition, the design also has the audio inputs from R5 and R6 for the Pokey and TIA to be attached to as well. From there the UAV then sits onto the pins pointing up and align with the vias on the UAV. Initial testing is possible by appling light pressure onto the UAV to ensure a decent connection with the pins so that you know the UAV and your soldering on the mount board is good. Then, you solder the UAV to the pins for a semi permanent install. As I didn't see a need for a large empty board to mount the UAV onto, I also added the chroma fix circuit along with the added resistors and capacitor for proper audio mixing and a convenient solder pad for the audio output wire to attach to. 

So in essence, you just solder your wiring to the output vias on the UAV for whatever you plan to use either composite or s-video or both, and after soldering the UAV into place, you run a wire from the audio output pad to your RCA jacks or whatever you decide to use for audio output jacks.

Here is the first one of these I assembled where I used single pin sockets so that the UAV could be taken on/off the mount board easily. This was only for testing and actual install would have the UAV soldered securely in place. This also means that the UAV won't stand quite as tall off the mount board as you see in the picture below because it would only be about half the height off the mount board soldered directly.

Here you can see where the pcb interconnect pins are soldered to the resistor legs on the board.

 

Here is the 2 pins that get soldered down for the audio signals for Pokey(External audio line) and the TIA.

 

Here is the test board with the UAV installed on top. Again the actual installs and use of this board will have the UAV sitting half as tall from the mount PCB.

 

I also designed vias for the +5 and GND that line up with the +5 and GND from the RF modulator interface board. This was so I could use right angle headers to solder on top of the original pins off the RF modulator and then go into the mount PCB. But this isn't as simple to do as it might seem so those vias doesn't even have to be used. Instead power and ground wires could be soldered to those vias more easily or even to the large +5 and GND pads on the UAV itself to power everything. 

I've already started talking with Marlin over at the Brewing Academy about making these available as either separate boards or as part of a larger all in one complete 7800 kit. Nothing set in stone with them yet but I do think this will make DIY types more apt to try and install UAVs into their own 7800s without having to worry about everything being in the right place or worry about wiring coming loose from the resistors etc. Only wiring really needed here is from the output side to your AV jacks.

Any thoughts on this? Anything that seems confusing? Or perhaps it is overkill? 

 

[RickR]

I think this is awesome. 

My main thought is that I'd probably just send my 7800 to you to do the mod. 

 

[CrossBow]

4 hours ago, RickR said:

I think this is awesome. 

My main thought is that I'd probably just send my 7800 to you to do the mod. 

 

What is interesting about you saying that, is The Brewing Academy actually thinks this will make the process so much easier and less daunting for budding DIY types they fear it will take away business from me if I make these publicly available and have them as part of a kit already? My intention with the work I do was never to make it a full time job as I have a full time job already. My intentions on the console work has always been to help people get their systems working again and perhaps offer a means to make it easier for these classic and vintage consoles to be enjoyed on both CRTs and modern displays.

TBA really seems interested in being able to make and provide these. So we shall see if I'm able to work out something with them. If nothing, else the next 9 atari 7800s that should come in for UAV upgrades, will at least have this initial idea installed into them.

 

[RickR]

I understand, and I'm totally onboard for this type of DIY kit.  Hopefully, and easy-to-follow, illustrated guide is also part of the plan. 

[CrossBow]

Well I already have the original UAV install guide for the 7800 I did several years back. The only difference here is that there aren't any wires to attach the UAV up itself. Just the wiring that still needs to be done to run to your AV jacks on the console where ever a person happens to install them etc.

I would honestly like to keep this board set for myself as a mark of my installs so to speak. But I haven't the resources to make these on a large enough scale I don't think and Brewing Academy actually own a pick n place machine for making their stuff. So they can have bare PCBs made and populate and make them in a fraction of the time it takes me. 

Really as long as everyone knows where and whom designed them, I think that is all that really matters.

 

[7800 Pro Gamer]

I read semi permanent there.  Am I to take this as I don't have to remove the rf modulator or any other components?  The mod I did to my 7800 required me to remove components that would make it difficult to ever return it to stock, which is something I doubt I'd ever want to do anyway but it always made me nervous.  If I screwed up, well I removed the rf so I either had to fix my mistake or find a way to reinstall the old components.

I've installed modchips to the Xbox and did TSOP mods, and the RGH and JTAG Xbox 360s.  I also did some internal Dreamcast and ps1 mods, but I still consider myself novice, so I'm all for simplicity and ease of install.

[CrossBow]

I state it is semi permanent because it isn't that simple to remove the mount once it is in place. But, no components have to be removed as I designed it to fit with the RF modulator left in place. That is part of the reason for the output side of the UAV having to stay on the left side of the mount board. To turn it around, meant that the UAV would end up being in the way of the audio tuning coil and that would have to be removed or resoldered in a different fashion. Or the UAV would end up hanging over the 74x logic ICs and make it difficult to replace those should it be needed in the future etc. 

I've managed to remove the mount but it took using my desoldering gun and having to carefully use a screw driver to pry the pins away form the resistor legs with the iron on them to loosen them up. So that is why I state it is semi permanent. But leaving it in place doesn't effect the RF output and vice versa.

Sounds like you did the simple composite only video upgrade on yours and that requires removing the RF and some other components because leaving them would cause interference in the composite output. The simple comp mod is just an amplifier that is boosting the original composite video that went into the RF modulator. So it is very susceptible to interference as a result. The UAV is a replacement video encoder circuit so it takes in the separate video signals needed and creates its own composite and s-video output. That is why it doesn't require having to remove anything and being able to leave the 7800 in stock condition. It is also why the UAV provides a better quality composite and really good quality s-video output as a result.

Now, the mount PCB does increase parts costs of course and they weren't cheap for me to have made up. Because I still end up having to hand solder everything together on them. So... in my installs it adds another $10 to the cost of parts, but due to time savings for actual installation, I dropped the labor costs $10 to compensate. Not sure what TBA will charge for them if they decide to go forward with having more made and using them.

But I think with all the confusion that exists with different methods to install the UAV depending on the Atari system you want to install it into, that an agreed standard method would make it way easier for everyone. So it would mean that the 7800 version of the kit would likely cost more than just installing a basic board, but the fact that additional work isn't needed for audio and it corrects from some of the chroma shifting a bit, plus allowing an easier to install method for everything really makes up for it I feel.

If you order a basic UAV (What I was doing prior to this), I still had to order separate 10µf caps and sets of 6.8k and 18k resistors for the audio mixing that had to be hand soldered together. The chroma fix was another PCB with a 100nf cap and 4050 IC chip on it that was assembled and soldered into the chroma line as well. So when you think about it, I wasn't really saving any money or time with the basic kit installs I'd been doing for the past several years. I'd gladly pay an extra $10 to have the extra stuff included and already done in a way that I don't have to do any additional wiring other than to my outputs. And that is what the UAV mount allows for.

BTW here are some additional pics of the latest one I did for a client. They had a previous... 'HDMI' install done and that had to all be ripped out. But as a result the RF modulator was already removed from the previous install. The UAV doesn't require having to put those components back, other than the C10 cap that the simple comp mod has you remove that affects the pokey audio. So that was the only component replaced.

This is the client's main board setup with the UAV soldered into place and using my test wire harnesses for burn in testing. Composite output on the small PVM and S-video on the larger LCD.

 

Here is a closeup view of the UAV installed during testing...

 

Here is the complete UAV and new BIOS install that the client also requested to have done.

And here are two sample pics of the s-video output directly from the flat panel LCD. This is an older multi input computer monitor so it has s-video, component, composite, DVI, and VGA inputs. I use a DVI to HDMI converter for Retrotink2x SCART usage when doing RGB installs. But you get a good look at the quality of the s-video output from a UAV. In many cases, I'd be happy enough with this and while an RGB output for the 7800 is eventually coming, I'm good with waiting while the s-video looks this good.

 

Edited June 12, 2022 by CrossBow

[CrossBow]

I forgot to update this I guess? These UAV 7800 mount boards can now be purchased from the The Brewing Academy directly as they have the plans and everything to take over making them.

I've created an updated install guide specifically using the mount board that is attached to this post, and created a new install video highlighting the use of the mount board.

 

UAV_Install_A7800_Mnt_Brd.pdf