WienerWuerstel Posted February 15, 2015 Share Posted February 15, 2015 Hi Guys, I finally bought an Atari 7800 on ebay. I took the chance to buy it this time because the price was fair and it was already av modded, but there is a problem. The picture is fine during 2600 games and it actually looks great, but when I play Asteroids the picture becomes really unstable and changes colors. It wasn't that bad at first but it actually got worse IIRC. After some research I found that this phenomenon was called "TIA Interference" but not a way to fix. Is there an "easy" fix for it or did I just have bad luck again? Quote Link to comment Share on other sites More sharing options...
atariguy1021 Posted February 15, 2015 Share Posted February 15, 2015 Which mod is it? What you refer to as "TIA Interference" is only relevant if it's the Longhorn mod, does the console output S-video? This interference usually only causes diagonal interference lines and can be resolved by installing a switch that severs a connection during 7800 play. Here's a thread where that issue and solution is discussed: http://atariage.com/forums/topic/194761-troubleshooting-diagonal-lines-on-video-mod/ However, what you're describing sounds a bit more sinister than that. I could be wrong, I always install a switch on my Longhorn modded consoles and haven't done a lot of testing with the TIA connection intact during 7800 play. Quote Link to comment Share on other sites More sharing options...
WienerWuerstel Posted February 15, 2015 Author Share Posted February 15, 2015 Thanks for the quick response. It's a composite AV Mod . I sadly don't know which one it is exactly because I didn't install the mod myself, and the seller didn't tell me which mod he used. I assume that he followed this tutorial: http://circuit-board.de/forum/index.php/Thread/2436-TUT-Atari-7800-AV-Video-Mod/. But that's just a guess. Quote Link to comment Share on other sites More sharing options...
atariguy1021 Posted February 16, 2015 Share Posted February 16, 2015 If it's a composite only mod the thread that I linked you to doesn't apply. Unfortunately, this is probably not an easy fix. Have you contacted the seller? I sell modded 7800's on ebay and always work with people when issues arise, which they sometimes do. Quote Link to comment Share on other sites More sharing options...
Rick Dangerous Posted February 16, 2015 Share Posted February 16, 2015 There should be a switch somewhere to cut the Tia interference. Try the channel switch in both positions. Quote Link to comment Share on other sites More sharing options...
atariguy1021 Posted February 16, 2015 Share Posted February 16, 2015 There should be a switch somewhere to cut the Tia interference. Try the channel switch in both positions. If it's a composite only mod there's no such switch. Unless by some rare chance the seller used the Longhorn mod and omitted the S-video out, but that's unlikely. Quote Link to comment Share on other sites More sharing options...
WienerWuerstel Posted February 16, 2015 Author Share Posted February 16, 2015 Yeah, I tried the switch but that didn't help. The ebay seller also sent me an replay and asked me which TV I use and what brand it is. That kinda shows me that this guy really doesn't know which mod is installed and how to fix it. I could be wrong but that reply didn't give much hope. Unless it really matters on which brand TV the 7800 runs, which would be news to me. Quote Link to comment Share on other sites More sharing options...
atariguy1021 Posted February 16, 2015 Share Posted February 16, 2015 The seller may just be grasping at straws with the TV thing, but it is a good idea to try the console on another television just so you can rule the TV out as the problem. If you try it on another screen and get the same result you know it's the console. If you're not comfortable opening the console you can still try some basic things and hope for the best. If you have another 7800 power supply give it a try and see if you get the same result. Also, clean the cart connector thoroughly and look for any pins that might be bent or not as far out as the others. Since your problems are confined to 7800 games pay particular attention to the 8 outer most pins (four on each side). I'm not too hopeful that these basic things will resolve your issue... but they're worth a try. Quote Link to comment Share on other sites More sharing options...
Rhomaios Posted February 16, 2015 Share Posted February 16, 2015 It's really easy to open up a 7800, though. Just a few screws to keep together. Quote Link to comment Share on other sites More sharing options...
atariguy1021 Posted February 16, 2015 Share Posted February 16, 2015 It's really easy to open up a 7800, though. Just a few screws to keep together. Haha! That's true, there are a mere 5 screws holding it together. What I meant is if he didn't feel comfortable or knowledgeable enough to work on anything inside the console. Quote Link to comment Share on other sites More sharing options...
WienerWuerstel Posted February 16, 2015 Author Share Posted February 16, 2015 Already tried on different TV with the same result. Can't try another power supply because I only have the one that come with the console (It's a shame that the 2600 power supply doesn't work). The pins in the cartridge slot couldn't be a problem because the problem occurs when I play Asteroids, which is already pre-installed in the 7800 (PAL).I don't have any other games right now. Cleaning it is always a good thing though. Opening the console wouldn't be a problem, the bigger problem is finding the electronic component that is causing the issue. It could be as easy simply adding or removing a resistor or a bigger problem. PS: I'm really grateful for the help from you guys. It isn't that common nowadays to find such a nice community. Quote Link to comment Share on other sites More sharing options...
atariguy1021 Posted February 16, 2015 Share Posted February 16, 2015 I didn't think of Asteroids not being an actual physical cart, so that definitely rules out the cart connector as you said. The power supply is likely not the issue either but would of been worth trying if you did have an extra on hand. Quote Link to comment Share on other sites More sharing options...
FireTiger Posted February 17, 2015 Share Posted February 17, 2015 Any other 7800 games, maybe the onboard game got corrupted?Maybe Maria is 'off' (I have a 7800 that won't display any 7800 games.) Quote Link to comment Share on other sites More sharing options...
WienerWuerstel Posted February 17, 2015 Author Share Posted February 17, 2015 I can't try any other 7800 games because I only have Asteroids but I'm going to Subotron tomorrow and buy some games. Hope they have Food Fight 1 Quote Link to comment Share on other sites More sharing options...
atariguy1021 Posted February 17, 2015 Share Posted February 17, 2015 Yeah, I'm with FireTiger on this one... You're going to want to try another 7800 game other than the built-in Asteroids. I guess I shouldn't of assumed that you had, Good Luck! Quote Link to comment Share on other sites More sharing options...
WienerWuerstel Posted February 18, 2015 Author Share Posted February 18, 2015 Well he didn't have Food Fight but I got Joust instead. That's the good news. The bad news is that I still get the same result (changing colors, unstable picture), The seller just sends me the same thing over and over again. He claims that nothing is wrong with the console and that he sold 10 of them and none of them had a problem. He also repeats that I should change the channel to 0 or AV. Guess I had bad luck this time. Quote Link to comment Share on other sites More sharing options...
+Zeptari Posted February 18, 2015 Share Posted February 18, 2015 To bad about the food fight. Excellent game btw. It happens to be the first cart I found out in the wild for my newly acquired 7800. But joust is a really great port. Graphics and audio seem spot on. Everyone rags on the 7800 audio, but most of mine seem very impressive. Quote Link to comment Share on other sites More sharing options...
Rhomaios Posted February 18, 2015 Share Posted February 18, 2015 First of all, Joust is great. I like it even better than Food Fight, and this is a great port of it. Perhaps the best, even including the sound. Second, the seller is a crack if he is ignoring the fact that 2600 games play fine. It's probably not likely the mod, though, if that's the case. I'm not an expert in these matters, but I would suspect something's wrong with MARIA or something else that's interfering with processing the 7800 directly. It also sounds kind of similar to Jagosaurus' problem. Maybe open it up, take some pictures, see what's going on if there's anything missing? http://atariage.com/forums/topic/220365-7800-plays-2600-games-not-7800-games/ Quote Link to comment Share on other sites More sharing options...
atariguy1021 Posted February 18, 2015 Share Posted February 18, 2015 I'd keep pressing the seller. His experience with other consoles that he has sold is irrelevant. It doesn't even matter if it's a problem that he didn't experience when testing this console, bottom line is you are experiencing the issue and he should work with you to make it right. Unfortunately, my earlier feeling that this wouldn't be a simple fix holds true. I've seen a couple people in this thread reference Maria as a possible culprit and I agree that is a logical starting point because I don't think your issue is due to the mod but rather the console. However, I've had a few boards that I've just giving up on repairing that had issues that I believe are similar to what you're describing, strange graphical issues during 7800 play. In those cases I've swapped out Maria, along with every other IC specific to 7800 play, replaced the cart connector, the 3 electrolytic caps, voltage regulator, etc... all to no avail. But now since I've received an abundance of 7800's where the shell is damaged, I have more boards than shells, so I now quickly relegate these troublesome PCB's to parts boards. I hope to eventually find the component responsible by using it for another console... no luck yet. Quote Link to comment Share on other sites More sharing options...
WienerWuerstel Posted February 19, 2015 Author Share Posted February 19, 2015 Opened the 7800 just now and I can't see what's wrong. The AV Mod looks fine AFAIK and MARIA lokks also OK. The solder joints look also good, so it seems that whoever modded this console knew at least how to solder or/and had steady hands I made some (crappy) pictures of the board so you can take a look at it. Let me know if you want to have a picture of a certain area on the board. http://imgur.com/a/BcGCL I already gave up on the seller. He seems to think that it isn't his fault and wants to send me videos and pictures of his other modded consoles that seem to work. He doesn't seem to realize that this doesn't help any of us Quote Link to comment Share on other sites More sharing options...
Rhomaios Posted February 19, 2015 Share Posted February 19, 2015 Opened the 7800 just now and I can't see what's wrong. The AV Mod looks fine AFAIK and MARIA lokks also OK. The solder joints look also good, so it seems that whoever modded this console knew at least how to solder or/and had steady hands I made some (crappy) pictures of the board so you can take a look at it. Let me know if you want to have a picture of a certain area on the board. http://imgur.com/a/BcGCL I already gave up on the seller. He seems to think that it isn't his fault and wants to send me videos and pictures of his other modded consoles that seem to work. He doesn't seem to realize that this doesn't help any of us For those who click on that link and it doesn't work, remove the %20 at the end. Not sure why it's doing that. Quote Link to comment Share on other sites More sharing options...
WienerWuerstel Posted February 19, 2015 Author Share Posted February 19, 2015 (edited) Can't seem to be able to edit my post so I'll post the link in raw form: http://imgur.com/a/BcGCL Now it should work Edited February 19, 2015 by WienerWuerstel Quote Link to comment Share on other sites More sharing options...
FireTiger Posted February 19, 2015 Share Posted February 19, 2015 (edited) Have you escalated the clam if via paypal or ebay?You should have a working console. This one fails to work as expected- he should 'RMA' this one for you. Edited February 19, 2015 by FireTiger Quote Link to comment Share on other sites More sharing options...
WienerWuerstel Posted February 19, 2015 Author Share Posted February 19, 2015 Would a claim work in this case? I didn't pay via paypal and is there even a warranty on a used console? Never tried that so I'm curious. Quote Link to comment Share on other sites More sharing options...
FireTiger Posted February 19, 2015 Share Posted February 19, 2015 Did you get it on Ebay? check thier policy out. I'm not sure I tend to pay with paypal.You bought a console with the expectation that it played 2600 and 7800 games, this one does not... Was it advertised "plays 7800 and 2600 games? If so the "condition is not as described." look into it Quote Link to comment Share on other sites More sharing options...
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