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Old 21st Feb 2021, 8:26 pm   #611
julie_m
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Join Date: May 2008
Location: Derby, UK.
Posts: 7,732
Default Re: Non-working Commodore PET 3016

Quote:
Originally Posted by SiriusHardware View Post
Thanks for the detail, you obviously know your 6502 very well.
Thanks for the compliment! Sign of a mis-spent youth, probably.
Quote:
Originally Posted by SiriusHardware View Post
I'm hoping in the first instance that if there is a fault on one of the buffers it will make itself more obviously known and not be as subtle as you suggest.
Yes, perhaps I was being a bit pessimistic. Mind, anything's going to look a bit disappointing after that absolute money shot of the fault on the address buffers! It will all depend on the nature of the fault. Pin 5 seems not to be pulling low enough, but will it do it with the CPU disconnected?
Quote:
Originally Posted by SiriusHardware View Post
If not, we'll try as you say, but as Colin already has a couple of replacements 'on shed' it may ultimately be more straightforward to replace them to rule them in or out - they are after all the same device, possibly the same batch, same age, performing a similar function to the address buffers which weren't working very well.
Indeed; and I'm confident that replacing UE9 and UE10 will produce some improvement. Maybe even a BASIC prompt, although that's probably a little too much to hope for.
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