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Old 15th Apr 2021, 5:26 am   #1664
ortek_service
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Location: Northampton, Northamptonshire, UK.
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Default Re: Non-working Commodore PET 3016

Quote:
Originally Posted by ScottishColin View Post
OK - so here's a thing that may be useful to others.

While I'm waiting for the conductive paint to turn up, I tried something I've seen recommended elsewhere. I took a normal A4 blank sheet of paper and folded it up. Carefully, I rubbed it on each of the conductive pads on the bottom of the keys. It actually got quite dirty. I plugged/screwed the keyboard back together and all the keys bar 4 worked just fine.

I gave those 4 a working over with the paper and I now have a fully working keyboard. So I guess I've gone too early on the conductive paint, but if my paper-rubbing fix turns out to be temporary, it'll be useful.

Anyway - the keyboard is screwed back in and fully working.

What remains now is to test the ports - I can test the second cassette port easily enough.

Can anyone help with code to test the remaining ports?

Colin.
That's useful to know, and surprising that the originally-used IPA cleaning fluid hadn't completely cleaned the surface whereas try paper had! (Not sure if "Rubbing Alcohol" mentioned elsewhere is much different.
Although I have sometimes gently-scraped the surface of the conductive rubber with a flat-blade screwdriver / finger nail and noticed the surface change colour slightly from shiny black to more grey.
So maybe there is some stubborn muck that didn't shift too easily.
But I have sometimes worried that too much scrubbing with IPA etc. may remove conductive coating if that is mainly just on the surface and not embedded into the whole of the black-rubber part.

I presume the Diagnostic test firmware etc, mentioned in other places would test the other ports. There is a diagnostic loopback connector wiring for the User Port, but not about the parallel port.
Although it may be easier to just find what the PIA/VIA memory-mapped register locations are, set the control registers for the correct directions and write all 1's / 0's to all the datalines / control lines.
Then run a loop to read the registers for all the input lines (after resetting direction register for all inputs), and pull each input high & low in turn.
And I do recall some test routine listings in some of the PET books I found, with many of these at the bottom of: http://www.primrosebank.net/computers/pet/pet_docs.htm

Last edited by ortek_service; 15th Apr 2021 at 5:50 am.
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