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Old 18th Mar 2021, 2:28 pm   #1143
ajgriff
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Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
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Default Re: Non-working Commodore PET 3016

Quote:
Originally Posted by ScottishColin View Post
Tried this - no difference (ie blank screen which has power).
That's actually quite informative if the 2001-8 is anything to go by because it suggests that:

1. The PET might be getting past the character screen stage of the boot process without the PIAs in place.

2. At least one of the PIAs is probably faulty.

For what it's worth both 6520 PIAs were faulty in my PET. Failure of PIA2 resulted in the random character screen and PIA1 caused a problem with the internal datasette port.

I wouldn't do anything about the PIAs at the moment. Leave that until progress has been made with the RAM issues. Ultimately if one or both PIAs needs replacing there are reasonably priced alternatives to the original 6520s. Perhaps best to cross that bridge when we come to it.

Alan
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