root42 Posted July 22 Share Posted July 22 I bought the BA UAV mod to give my PAL 7800 composite and SVideo out. The installation manual only deals with the NTSC board. My PAL board looks completely different, using the bodge PCB for the SRAMs and the general layout is different: I have looked the schematics of both board revision, and beeped out all of the signals required, except the TIA Color signal: Now I THINK that TIA Color should be picked up at R17. But since the silkscreen is BELOW the components, I don't know which one is R17. I was thinking it would be the second resistor from the right in the cluster next to the RF modulator. However measuring from pin 9 of TIA I read 1.4kOhm instead of 0Ohm. I probed around a lot, but couldn't find a good spot to pick up the signal. Any idea? Quote Link to comment Share on other sites More sharing options...
mimo Posted July 22 Share Posted July 22 Is this any help? Quote Link to comment Share on other sites More sharing options...
root42 Posted July 22 Author Share Posted July 22 Perfect! It's R37! Quote Link to comment Share on other sites More sharing options...
root42 Posted July 22 Author Share Posted July 22 One note though: At least according the schematics, pin 11 of the 74LS32 should be Sync, which is connected to the 2nd resistor from the bottom in the cluster next to the RF modulator. However in the pic from the other thread it is the third resistor: I will break out the scope to check which of the resistors really has the sync. Quote Link to comment Share on other sites More sharing options...
root42 Posted July 22 Author Share Posted July 22 Alright, it seems that the PAL schematic is incorrect. The other thread is indeed correct and the third resistor has the CSYNC sygnal: Blue in this case is the third resistor. This means that pin 11 of the 74LS32 does NOT contain the CSYNC signal. Are there any other schematics available? I pulled mine from Retrosix: https://www.retrosix.wiki/schematics-atari-7800 Quote Link to comment Share on other sites More sharing options...
root42 Posted July 22 Author Share Posted July 22 I googled around for C300633-001, which is the board revision I have, and found this neat schematic! This seems to be correct. CSYNC comes out of pin 8 of the 74LS32. Quote Link to comment Share on other sites More sharing options...
juansolo Posted July 22 Share Posted July 22 (edited) This is for a different mod hence loads of parts have been pulled, but it should help: EDIT: for audio I now pull up the left hand side of the two resistors above C55, put them together than output it through a 10u cap. The older mod this picture was taken for grabbed it from the above places as it had the audio bits on board. We do this now: Edited July 22 by juansolo 1 Quote Link to comment Share on other sites More sharing options...
root42 Posted August 4 Author Share Posted August 4 So I finally installed the mod and I only get black and white output. I habe checked TIA color in and Maria color in, and both have a sensible signal on them. However the chroma out stays at 1.36V and a bit noisy. Composite video has an image but no color. How do I debug this? Quote Link to comment Share on other sites More sharing options...
juansolo Posted August 5 Share Posted August 5 (edited) The TIA (2600) chroma (R35 RHS) goes to T.Col and the Maria (7800) Chroma (R25 LHS) goes to CO In. If that's correct and there appears to be chroma signal on your scope at those points and you're still not getting colour in your composite out, it could be that you need to adjust the colour trimmers. The top one you can see is the 7800 one, the other is underneath that daughter board and that adjusts the 2600 colour. Edited August 5 by juansolo Quote Link to comment Share on other sites More sharing options...
root42 Posted August 5 Author Share Posted August 5 @juansolo There is no trimmer on the bottom side (I have a Rev D board), and adjusting the trimmer on the top does absolutely nothing. And yes, we checked both color inputs, and they seem to be getting perfectly good signals. Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted August 5 Share Posted August 5 26 minutes ago, root42 said: @juansolo There is no trimmer on the bottom side (I have a Rev D board), and adjusting the trimmer on the top does absolutely nothing. And yes, we checked both color inputs, and they seem to be getting perfectly good signals. Try to apply some pressure to the various ICs on the UAV by gently pinching them between your fingers. I believe most of the UAVs were actually made up several years ago and it is possible for some of the solder connections to have come loose from the ICs due their handling and such. I've only had it happen about 4 times now, with 1 I wasn't able to fix where it had a similar issue. I just had to apply a little flux to the IC legs and carefully went back over them with my iron to apply some fresh heat to get the solder to remelt again. It isn't super common to have to do this, but I've had to do it a few times. Pressing on the ICs lightly while you have a game up will demonstrate if this is an issue for you. Also make sure you didn't accidentally remove any of the small SMD stuff on the bottom side of the UAV. Quite a few of those components near the output vias have to do with attenuating and buffering the output signals. I've had one or two of those small caps come loose when soldering in header pins in the past since there isn't a ton of clearance on the bottom side of the board. Quote Link to comment Share on other sites More sharing options...
root42 Posted August 5 Author Share Posted August 5 @-^CrossBow^- I tried, and pressing has zero effect. I also don't see any missing components. I can probe around the board with an oscilloscope, if I knew where the signals should be going, and which chip produces the actual chroma signal. Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted August 5 Share Posted August 5 26 minutes ago, root42 said: @-^CrossBow^- I tried, and pressing has zero effect. I also don't see any missing components. I can probe around the board with an oscilloscope, if I knew where the signals should be going, and which chip produces the actual chroma signal. The UAV design specifics is known only to the original developer and @MacRorie over at Brewing Academy. I've not tried to suss out all of the signals myself other than additional points where I can attach to if the normal vias are damaged or in one case I actually had a UAV with a faulty trace from manufacturing on the T-COL line back to the IC directly near it. So I had to bodge a wire into place on that install to get color on 2600 games working again. Again, defects with the UAV are pretty rare but can happen like anything else that is built by human beings. Quote Link to comment Share on other sites More sharing options...
+MacRorie Posted August 6 Share Posted August 6 10 hours ago, -^CrossBow^- said: The UAV design specifics is known only to the original developer and @MacRorie over at Brewing Academy. I've not tried to suss out all of the signals myself other than additional points where I can attach to if the normal vias are damaged or in one case I actually had a UAV with a faulty trace from manufacturing on the T-COL line back to the IC directly near it. So I had to bodge a wire into place on that install to get color on 2600 games working again. Again, defects with the UAV are pretty rare but can happen like anything else that is built by human beings. All UAVs are either made by a factory in a clean room and then individually packaged in SMD bags OR if I need to make some between shipments, they are made with a pick and place and a reflow oven in my shop. Of the literally 1000s of UAVs sold, there have been maybe a handful that have been faulty from the factory (as noted by @-^CrossBow^-. I have looked over this conversation and I am not certain if you are using a BASIC board and installing from there or a BASIC board on a ITC carrier. If the latter, check to make sure you have good solder connections between the ITC board and the UAV. Also, the solder points on the UAV are VERY sensitive to too much heat and can lift fairly easily, so I would make sure you have good connections all around (as I am sure you have, but check anyway ). -M Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted August 6 Share Posted August 6 55 minutes ago, MacRorie said: All UAVs are either made by a factory in a clean room and then individually packaged in SMD bags OR if I need to make some between shipments, they are made with a pick and place and a reflow oven in my shop. Of the literally 1000s of UAVs sold, there have been maybe a handful that have been faulty from the factory (as noted by @-^CrossBow^-. I have looked over this conversation and I am not certain if you are using a BASIC board and installing from there or a BASIC board on a ITC carrier. If the latter, check to make sure you have good solder connections between the ITC board and the UAV. Also, the solder points on the UAV are VERY sensitive to too much heat and can lift fairly easily, so I would make sure you have good connections all around (as I am sure you have, but check anyway ). -M @MacRorie No this on a PAL model console that is being discussed so the ITC mount board wouldn't be used here. Can't be used as the layout on the PAL and NTSC mainboards are too different in that regard. I was just trying to find some ideas on why the OP is getting only black and white output. Without any pics to see how everything is connected it is all guess and speculation. Quote Link to comment Share on other sites More sharing options...
root42 Posted August 6 Author Share Posted August 6 6 hours ago, -^CrossBow^- said: @MacRorie No this on a PAL model console that is being discussed so the ITC mount board wouldn't be used here. Can't be used as the layout on the PAL and NTSC mainboards are too different in that regard. I was just trying to find some ideas on why the OP is getting only black and white output. Without any pics to see how everything is connected it is all guess and speculation. I will try to add pictures tonight. I have used the PAL instructions from the thread linked above. As mentioned I have tested with an oscilloscope that all the signals arrive at the UAV board, which they seem to do. But maybe someone finds an issue on my pictures, once I get to upload them. Quote Link to comment Share on other sites More sharing options...
root42 Posted August 6 Author Share Posted August 6 Here are the pictures. It looks a bit haywire, but I closely followed the steps from this thread. Quote Link to comment Share on other sites More sharing options...
marauder666 Posted August 7 Share Posted August 7 Have you tried turning the trimmer on the motherboard, that adjusts the 7800 colour. There's another one for the VCS side, but its under the RAM daughterboard on yours, stupid Atari. Maybe theres access to it from the underside. Quote Link to comment Share on other sites More sharing options...
root42 Posted August 7 Author Share Posted August 7 3 minutes ago, marauder666 said: Have you tried turning the trimmer on the motherboard, that adjusts the 7800 colour. There's another one for the VCS side, but its under the RAM daughterboard on yours, stupid Atari. Maybe theres access to it from the underside. Again: the color signals arrive correctly at the UAV board, and color is fine on RF out. But the chroma out is sitting dead at 1.36V with a bit of noise. I don't see how tweaking the (correct) inputs would solve that. Hence the question: where on the UAV should the chroma signals go, and what should they look like? Then I can probe that with my scope. Quote Link to comment Share on other sites More sharing options...
marauder666 Posted August 7 Share Posted August 7 (edited) It changes the phase of the colour signal, if its too far out then the colours are wrong, even more out and the colour decoders in the TV don't even bother trying to decode it. Usually, it wont need much to get the colour back. Edited August 7 by marauder666 Quote Link to comment Share on other sites More sharing options...
root42 Posted August 7 Author Share Posted August 7 14 minutes ago, marauder666 said: It changes the phase of the colour signal, if its too far out then the colours are wrong, even more out and the colour decoders in the TV don't even bother trying to decode it. Usually, it wont need much to get the colour back. But the UAV won't mind right? Because its Chroma output is just dead. And RF works perfectly fine, as I said. Quote Link to comment Share on other sites More sharing options...
marauder666 Posted August 7 Share Posted August 7 That definatly sounds like issue with the UAV or the wiring Quote Link to comment Share on other sites More sharing options...
+MacRorie Posted August 7 Share Posted August 7 14 hours ago, marauder666 said: That definatly sounds like issue with the UAV or the wiring I would double check all of the solder points and the wiring. It would be *highly* unusual for the UAV to output *nothing* on the CHR or LUM points. -M Quote Link to comment Share on other sites More sharing options...
root42 Posted August 8 Author Share Posted August 8 8 hours ago, MacRorie said: I would double check all of the solder points and the wiring. It would be *highly* unusual for the UAV to output *nothing* on the CHR or LUM points. -M I did. Twice. It doesn’t output nothing. Luma is fine, Chrome is a noisy 1.36V flatline. Hence why I want to measure on the board where the signal disappears. Quote Link to comment Share on other sites More sharing options...
juansolo Posted August 8 Share Posted August 8 (edited) They're not going to release the schematic to the board, best to return it to Brewing Academy and get a replacement if the fault traces back there. Edited August 8 by juansolo Quote Link to comment Share on other sites More sharing options...
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