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Old 1st Jan 2021, 7:51 pm   #5
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 810
Default Re: Non-working Commodore PET 3016

Hi Colin,
Try measuring 5v power supply at each IC on the board first. On the 14 to 20 pin ICs this should be top left 5v and bottom right 0v as viewed when reading the markings on the top of the IC. That would put a pip or notch in the plastic of the IC at the left end of the IC.

As you already said this was bought non working, check for any empty sockets that might have been robbed in the past.

This is only a general guide to locating power on the ICs so let us know the details of any that donít have 5v.

Iím not sure if the 3016 has multiple supplies at 12v, -5v or -12v, but check the 5v first.

Scopes are a bit pricey for a first start, but you might find a simple logic probe will help a lot. Something like this one, but note Iím only using this as an example, not recommending it.
Mine is from the dark ages made by micronta. You want to find one that can show high, low or undetermined levels and able to detect fast pulses.

Mark1960 is offline