SviRu Posted August 4, 2023 Share Posted August 4, 2023 I need help with original Atari800. PAL. This is what I see on the screen. I can hear Atari booting to memo pad. Tried to remove all expansion cards but no luck here. Thanks. Same on composite and RF output. Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 4, 2023 Share Posted August 4, 2023 Try reseating the 4050 chip on the mainboard. Press it down first, then lever it up gently and reseat it. If still a problem try and replace it. 4050 chips are cheap. Failing this it could be a bad transistor in the video circuit I guess. 1 Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 4, 2023 Author Share Posted August 4, 2023 (edited) 1 hour ago, Beeblebrox said: Try reseating the 4050 chip on the mainboard. Press it down first, then lever it up gently and reseat it. If still a problem try and replace it. 4050 chips are cheap. Failing this it could be a bad transistor in the video circuit I guess. Thanks I will try to reseat 4050 and CPU board at first. Do you know transistor number or where I can find it? One thing - it has 12k EPROM - I have never seen 12k - only 10k - is this something special? Early version? Edited August 4, 2023 by SviRu Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 4, 2023 Share Posted August 4, 2023 (edited) 48 minutes ago, SviRu said: Thanks I will try to reseat 4050 and CPU board at first. Do you know transistor number or where I can find it? One thing - it has 12k EPROM - I have never seen 12k - only 10k - is this something special? Early version? It's unlikely the CPU board tbh. If you re hearing things functioning it's just likely the video circuit. Try the 4050 first, it's here: fyi I think they are NPN Transistor 2N3904 Also this schematic might help: Edited August 4, 2023 by Beeblebrox incorrect info corrected 1 Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 4, 2023 Author Share Posted August 4, 2023 1 hour ago, Beeblebrox said: It's unlikely the CPU board tbh. If you re hearing things functioning it's just likely the video circuit. Try the 4050 first, it's here: fyi I think they are NPN Transistor 2N3904 Also this schematic might help: Thanks! I will tear it apart. Maybe even today. Can I borrow 4050 from lets say 1050? Or something else? 1 Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 4, 2023 Share Posted August 4, 2023 11 minutes ago, SviRu said: Thanks! I will tear it apart. Maybe even today. Can I borrow 4050 from lets say 1050? Or something else? Possibly, but they are dirt cheap to buy if not. If you need a guide to dismantling your 800 see my signature for my blog tutorial on how to install incognito as it includes a full pictorial step by step guide on how to open it up. Be careful of the plastic as it can be very brittle. Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 4, 2023 Author Share Posted August 4, 2023 4 minutes ago, Beeblebrox said: Possibly, but they are dirt cheap to buy if not. If you need a guide to dismantling your 800 see my signature for my blog tutorial on how to install incognito as it includes a full pictorial step by step guide on how to open it up. Be careful of the plastic as it can be very brittle. THANKS. The idea was to buy INCOGNITO for this unit... but it does not work so for now hands full I have read about super video board that fixes this issue without fixing it itself... it just replaces video circuit? Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 4, 2023 Share Posted August 4, 2023 (edited) Yup, super colour cpu board incorporates a uav which replaces the video circuit. It works very well alongside incognito. Between my step by step incognito install guide which is based on Flashjazzcat's videos on the subject, and those - installing it is relatively easy. Edited August 4, 2023 by Beeblebrox Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 4, 2023 Author Share Posted August 4, 2023 1 hour ago, Beeblebrox said: Yup, super colour cpu board incorporates a uav which replaces the video circuit. It works very well alongside incognito. Between my step by step incognito install guide which is based on Flashjazzcat's videos on the subject, and those - installing it is relatively easy. Opened A8. Moved most if not all chips. Reseated all the cards including CPU. Nothing changed. I guess I will try 4050 route first. I was wondering about buying https://lotharek.pl/productdetail.php?id=362 . I think it repalces all the video circuit on all ataris. I do not know it this makes any sense. I guess i does not since a8 has such a great svideo imho. Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 5, 2023 Author Share Posted August 5, 2023 2 hours ago, Beeblebrox said: Yup, super colour cpu board incorporates a uav which replaces the video circuit. It works very well alongside incognito. Between my step by step incognito install guide which is based on Flashjazzcat's videos on the subject, and those - installing it is relatively easy. One auestion. Is the atari 400/800 CPU board the same? I have 400 NTSC. But my 800 is PAL. Can I swap them? Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 5, 2023 Share Posted August 5, 2023 (edited) No point as even if they are the same boards for 400/800 the ntsc cpu board doesn't have the colourburst crystal on it which is needed for pal. I'd first get a new 4050 chip, then if that doesn't work look at the transistor. Lotharek's Spectre AV board is another equivalent to uav for example. Check out Flashjazzcat's YouTube vid on a comparison between the two. Might be worth getting a SpectreAv as readily available and at present Tf_hh's Super colour cpu board isn't something readily available as he builds them to order afaik. However as I say first eliminate the 4050 as the cause. Again because you can hear the Atari 800 polling/booting up this helps a lot. It will be the video circuit at fault I'd imagine. If it were the crystals or anything like the graphics chips, cpu or rom, etc you wouldn't be hearing it boot. Edit: as you have it open can you snap a few hi res pics of the main board and post them here? Top and bottom. Take a photo of the socket for the 4050. It's worth seeing if it needs cleaning, has oxidisation and/or is damaged, etc. Also check all traces around to make sure none are broken. Check for dry soilder joints, etc. Edited August 5, 2023 by Beeblebrox Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 5, 2023 Author Share Posted August 5, 2023 3 hours ago, Beeblebrox said: No point as even if they are the same boards for 400/800 the ntsc cpu board doesn't have the colourburst crystal on it which is needed for pal. I'd first get a new 4050 chip, then if that doesn't work look at the transistor. Lotharek's Spectre AV board is another equivalent to uav for example. Check out Flashjazzcat's YouTube vid on a comparison between the two. Might be worth getting a SpectreAv as readily available and at present Tf_hh's Super colour cpu board isn't something readily available as he builds them to order afaik. However as I say first eliminate the 4050 as the cause. Again because you can hear the Atari 800 polling/booting up this helps a lot. It will be the video circuit at fault I'd imagine. If it were the crystals or anything like the graphics chips, cpu or rom, etc you wouldn't be hearing it boot. Edit: as you have it open can you snap a few hi res pics of the main board and post them here? Top and bottom. Take a photo of the socket for the 4050. It's worth seeing if it needs cleaning, has oxidisation and/or is damaged, etc. Also check all traces around to make sure none are broken. Check for dry soilder joints, etc. Thanks. I have a question. Can I swap 400 GTIA NTSC to my dead 800 PAL? Will it boot? IT can boot to Black and white. I could confirm dead GTIA this way. Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 5, 2023 Share Posted August 5, 2023 I think you would have to swap both the Antic and GTIA NTSC chips into your pal board. (remember to get the orientation of pin 1 on each right). You can try. You can get failing GTIA chips as well as dead ones but as I suspect because you can hear it polling/booting to memo pad the rest of the 40pin chipset is likely ok and it's just your video circuit, (4050 or transitor). More knowledgable people on this forum would be better placed to comment but by all accounts looking at the CPU board and it's chips isn't likely the issue here. As mention in my previous post do those things and post the requested images, etc and let's get some more info and more eyes on this. Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted August 5, 2023 Share Posted August 5, 2023 Swap that GTIA out - it'll boot without colour if that was the problem. 1 1 Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 5, 2023 Author Share Posted August 5, 2023 (edited) 36 minutes ago, flashjazzcat said: Swap that GTIA out - it'll boot without colour if that was the problem. thanks. I'll do that today. Fingers crossed. Or... that would be easier. Can I swap the whole 400 NTSC CPU board into 800 PAL? Will it boot with no color? Edited August 5, 2023 by SviRu Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 5, 2023 Share Posted August 5, 2023 1 hour ago, SviRu said: Can I swap the whole 400 NTSC CPU board into 800 PAL? Will it boot with no color? You could try yes. FYI an ntsc cpu board doesn't have a PAL colourburst crystal so it wouldn't have colour. Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 5, 2023 Author Share Posted August 5, 2023 1 minute ago, Beeblebrox said: You could try yes. FYI an ntsc cpu board doesn't have a PAL colourburst crystal so it wouldn't have colour. Great. Wanted to know if it would not blew up. Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 5, 2023 Share Posted August 5, 2023 It should be ok. Might I suggest you do some googleing around and double check? I think they are the same cpu board for both 400/800 Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted August 5, 2023 Share Posted August 5, 2023 It will most certainly not blow up. Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 5, 2023 Author Share Posted August 5, 2023 1 hour ago, Beeblebrox said: It should be ok. Might I suggest you do some googleing around and double check? I think they are the same cpu board for both 400/800 Changed good 4050 from 600xl. Still the same issue. Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 5, 2023 Share Posted August 5, 2023 (edited) OK, so after research to check it's compatible try the cpu board swap. Then failing that it may well be a 2n3904 transistor at fault in the video circuit or another passive component in that circuit. Edit: btw you did check the 4050's socket, solder points, etc etc as well as popping the new chip in? Sometimes it's just a bad socket, broken trace., etc etc. Edited August 5, 2023 by Beeblebrox Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 5, 2023 Author Share Posted August 5, 2023 24 minutes ago, Beeblebrox said: OK, so after research to check it's compatible try the cpu board swap. Then failing that it may well be a 2n3904 transistor at fault in the video circuit or another passive component in that circuit. Edit: btw you did check the 4050's socket, solder points, etc etc as well as popping g the new chip. Sometimes it's just a bad socket, broken trace., etc etc. tried my best. Board looks very nice socket is clean and shiney. Touched the chip when working but that did not change a thing. I have just removed GTIA and put it back - that also did nothing. Socket looks nice. I might have to swap CPU board. Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 5, 2023 Author Share Posted August 5, 2023 Thank you all for help! Machine is FIXED! It was GTIA in the end. Took one from 600xl. Works perfectly Very happy 2 Quote Link to comment Share on other sites More sharing options...
Beeblebrox Posted August 5, 2023 Share Posted August 5, 2023 Cool. I've never seen a bad GTIA do that on screen before. Good to know. Incognito next!! Quote Link to comment Share on other sites More sharing options...
SviRu Posted August 5, 2023 Author Share Posted August 5, 2023 21 minutes ago, Beeblebrox said: Cool. I've never seen a bad GTIA do that on screen before. Good to know. Incognito next!! YES! Incognito incoming this week Time to play some prince of persia at last. Quote Link to comment Share on other sites More sharing options...
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