Atari 520ST doea not boot.

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xyz378537
Atarian
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Atari 520ST doea not boot.

Postby xyz378537 » Mon Jun 10, 2019 8:16 am

I recently bought an Atari ST520, when I plugged it to the original monitor, it didn't do anything, but, when plugged to a standard composite monitor, there was a white screen with wobbly stripes on it. When I took it apart and tested the CPU with an oscilloscope, I saw, that the CPU was halted, and, when reset, it only executed a few instructions, before halting again.
How can I fix it?
Thanks in advance!

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Arne
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Re: Atari 520ST doea not boot.

Postby Arne » Mon Jun 10, 2019 11:27 am

As always:
  • clean MMU/Glue sockets and check for bent pins
  • get the appropriate Service Manual and check the paragraph titled Troubleshooting a dead unit

Voltages are fine?
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xyz378537
Atarian
Atarian
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Joined: Mon Jun 10, 2019 8:05 am

Re: Atari 520ST doea not boot.

Postby xyz378537 » Mon Jun 10, 2019 6:43 pm

Yes, the voltages are good. I have also already cleaned the MMU and Glue chips, and it still does not want to boot.
Sorry for spelling mistakes, my autocorrect is broken again.


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