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atari-dna

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About atari-dna

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    Moonsweeper
  • Birthday 06/18/1974

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    Glen Allen, VA

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  1. Digikey has the capacitors and diodes, including the pigtail fuse. I’ll post part numbers tonight. It’s a very small board and some delicate work but not impossible to restore providing the transformer is good.
  2. Agreed. Make sure to save the sleeving and be cautious with the long leads when installing your replacements.
  3. True but there are modern replacements which work well 3M156065-ND is a Digi-Key part number for a solution to this problem.
  4. What’s the base look like? If you see two screws then there are two more hidden under rubber feet.
  5. You’ll have to open them up, inspect the fuse and diode bridge. One of the 1N5401 diodes is probably going bad. Measure the A/C ripple current on your output also, if it’s above just a few hundred millivolts that’s a dead giveaway the bridge diodes are failing.
  6. Looks like your system bios rom failed it’s checksum. There’s two versions of the bios, get a replacement here—choose four port for full compatibility with all games https://console5.com/store/atari-5200-4-port-bios.html
  7. Good. This supports my hypothesis. I’m going to post a photo of the pcb, where you should check for a solder blob. This was an issue on early production units and it sound like it’s exactly your issue.
  8. Yes this makes sense. Thank you for the explanation!
  9. If this is a 4 port unit (please confirm) then I suspect you have a shorting problem on a data line, near the cartridge port. Particularly as this is intermittent and can be fixed by wiggling/flexing near the cartridge port. It’s a known issue with earlier 4 port consoles. If you have a 4 port then I’ll explain further what you should look for.
  10. Have you checked the inter board cable for continuity? Headers and wires. These can be problematic.
  11. So, it’s quasi compatible—depending on the hardware implementation. If you need a halt signal you need to tinker, if not then it’s drop-in?
  12. Correct. The Sally is not directly compatible with a stock 6502 (opcode differences). There is an eBay seller that has these available. There’s also a board you can design to utilize stock chips but it’s fairly advanced tinkering. https://atariage.com/forums/topic/277464-sally-replacement-by-standard-6502/
  13. Okay! The double shot does work. I remembered it wrong, Supergun. Just holding the reset switch is all it takes. There is is no ability to rapid cycle through the game variations though ☹️
  14. When cleaning up my junior (large rainbow) unit I wanted to play a little Space Invaders for the burn-in. I attempted the “double shot” exploit by holding down rests and game select simultaneously then applying power. It doesn’t work. In fact, you can’t hold the buttons down together to cycle quickly through the variations either. Apparently the Mylar circuit won’t read these two buttons at once. This discovery takes a lot of the fun and user friendliness out of the gameplay of Space Invaders.
  15. After reviewing the schematics and revisions of 2600 hardware, I’ve noticed something peculiar about this bulletin that Atari circulated. Summary: The color output is tied to the blanking line with a resistor in a heavy 6, and later this was dropped (cost reduction?) then made available as an upgrade due to poorer color reproduction—finally the blanking resistor was incorporated back into the design. Here’s what is strange. The value of the resistor which was originally in circuit (heavy 6 R213) is 680 Ω the “update” stipulates an 820 Ω be inserted, which is about 20% greater resistance. Aside from that, all the other parts of this circuit are identical. So, why the boost on the resistor? Has anyone tried an 820 on a heavy? Or using a 680 on a 2600A? I wonder if there is a significant difference? I’ve always liked the color quality of the heavy and found the juniors also pleasing to the eye. Now I am tempted to compare and contrast the two while swapping the blanking resistor values. I’m interested to know which produces better color? Possibly a 1K pot could be dropped in there and tweaked to see if there is a “sweet spot”? Has anyone tried experimenting with this? Please let me know.
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