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NickFolino

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About NickFolino

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    Space Invader
  1. Just an update. This Pong is fixed. The 7404 and C12 were replaced. Works like new now.
  2. Thanks, Chas. I have a CRT TV I use for testing old computers. I have the pong apart and looked at it for a few minutes. The linked schematic above is hard to read and appears to have at least one error that I've found. This pong seems to have no clock pulses. I haven't figured out why yet, probably an issue with the chip, which would condemn this guy to the scrap heap :-( Nick
  3. Does anyone have a schematic for a C-100? I just picked one up and it goes from static to a black screen when powered on. Thanks. Nick
  4. Another GTIA chip solved all issues. It's working like new again. Nick
  5. FYI - I did find the service manual. It is a GTIA and it is bad. Adjusting would get any color from it.
  6. So I got a GTIA from ebay. I arrived in a bubble mailer with the chip stuck in a piece of styrofoam. Chip was no good, but it did help me prove that the GTIA was the fault. The new chip worked fine, but had no color. The seller is sending a replacement, hopefully not stuck in styrofoam. Nick
  7. I took it apart and cleaned all of the contacts, removed all socketed chips and cleaned those as well. Same problem. I found this post where a similar problem with the vertical line in Donkey Kong was fixed with a new GTIA. Guess I'll have to source one of those to try a swap. http://blog.tynemouthsoftware.co.uk/2018/11/atari-400-48k-internal-ram-upgrade.html Nick
  8. Thank you for the quick reply. I have de-oxited the cartridge slot, but being that I've never worked on a 400 I figured I'd ask for help before tearing into it. I'll tear it down, re-seat the boards and clean the contacts. Look for weak solder while I'm in there. It'll take me a few days to find the time, I'll let you know how it goes. Anything odd I need to know about tearing this thing down? Or is it pretty easy? Nick
  9. I'm looking for assistance in repairing an Atari 400. It has an intermittent issue with graphics. Sometimes it starts up fine and everything looks normal. When this happens the graphics and colors are fine until the computer is powered off. Other times the colors are off on startup, for instance sometimes when playing Donkey Kong from a cartridge the graphics on the title screen are green. Other times it starts with a white background. The only way to resolve this is to power cycle. Other times sprites are missing. For instance when playing Pac-Man from a cartridge Pac-Man and the ghosts are missing. You can still control the invisible Pac-Man by following the dots as they disappear. You will never die from hitting a ghost. Sometimes when playing Donkey Kong the Jumpman character is missing and just a solid vertical line runs down the screen at the position he should be in. Again only power cycling will resolve these issues. Any ideas what can cause this? Could it be the ANTIC? Any help would be appreciated. Nick
  10. And now it works! For some reason this one uses channel 2. No switch to change it.
  11. Thanks zylon. I'll look there.
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