Search found 4 matches

by Enzo1960
Fri Mar 31, 2017 4:40 pm
Forum: Guides
Topic: [SOLVED] Atari 520 STFM short circuit in main board +5V
Replies: 7
Views: 14971

Re: Atari 520 STFM short circuit in main board +5V

Today I built my Atari Diagnostic cartridge,so I hope to solve mystery: Result: RS232 output data, and, with a VT100 terminal I can read this line, repeated in loop: I1 RAM/data line error 0000000000000000 0000000000100000 000008 I searched in service manual how this output can help to identify defe...
by Enzo1960
Thu Mar 23, 2017 11:10 am
Forum: Guides
Topic: [SOLVED] Atari 520 STFM short circuit in main board +5V
Replies: 7
Views: 14971

Re: Atari 520 STFM short circuit in main board +5V

My digital tester shows short circuit, but I putted it in "continuity circuit" test mode. If I measure voltage with power supply connected it shows +5v, +12v. Otherwise if a similar short will exist on +5v line, surely some component will be hot, and no video appears.At video appears some sort of ga...
by Enzo1960
Mon Mar 20, 2017 6:56 pm
Forum: Guides
Topic: [SOLVED] Atari 520 STFM short circuit in main board +5V
Replies: 7
Views: 14971

Re: Atari 520 STFM short circuit in main board +5V

Thank you, although, because all in parallel, I've to disconnect almost one pin from every cap. But, in my opinion, perhaps I'm failed diagnosis. It is possible that Atari has a strong absorption pn +5v, and modern tester shows it as a short circuit. I'm thinking to build a diagnose card, so I can r...
by Enzo1960
Sat Mar 18, 2017 10:12 am
Forum: Guides
Topic: [SOLVED] Atari 520 STFM short circuit in main board +5V
Replies: 7
Views: 14971

[SOLVED] Atari 520 STFM short circuit in main board +5V

Hello! I recently bought an used Atari 520STFM, but it reveals not working. At video output it shows various vertical bars/garbage. I opened it, checked capacitors value & ESR, all regular. But when I check voltage on RAMs they shows a negative value! I measured voltage in J10 connector and they are...

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