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Old 4th Mar 2021, 1:03 am   #794
Timbucus
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Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
Posts: 1,362
Default Re: Non-working Commodore PET 3016

Quote:
Originally Posted by SiriusHardware View Post
What do you think the likely UH3 chip failure mode is though - failure of the clock input or the serial data input, perhaps? Certainly not failure of a single output.

This machine has definitely had a hard life. If only it could tell us its story.
Indeed - you do wonder - not sure if I would wince if I heard its life story...

I think it is likely internal either the AND gate (1/2) or the inverter on the clock input (8). As long as Pin 9 is held high then that has to be the cause.
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