UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Non-working Commodore PET 3016

SiriusHardware · 13th Jan 2021, 5:13 pm

Pin 8 of UG5 is 0V and of course the 0V rail goes to every other device and almost every connector on the PCB, so it would not surprise me if you found either a dead short or a resistance reading from there to quite a few other places on the PCB.

I must stress that if this was a rare, £30, 40 pin soldered IC we were talking about we would be considering almost every other option before chopping such a device to pieces without being certain whether it was faulty or not.

In the case of UG5 though, we are talking about a cheap and apparently still easily available IC, so it's no major loss if you cut the original UG5 up and it turns out not to have been the cause of the fault after all. Preservation of the PCB, rather than the IC, is the priority here.

13th Jan 2021, 5:13 pm	#110
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,586	Re: Non-working Commodore PET 3016 Pin 8 of UG5 is 0V and of course the 0V rail goes to every other device and almost every connector on the PCB, so it would not surprise me if you found either a dead short or a resistance reading from there to quite a few other places on the PCB. I must stress that if this was a rare, £30, 40 pin soldered IC we were talking about we would be considering almost every other option before chopping such a device to pieces without being certain whether it was faulty or not. In the case of UG5 though, we are talking about a cheap and apparently still easily available IC, so it's no major loss if you cut the original UG5 up and it turns out not to have been the cause of the fault after all. Preservation of the PCB, rather than the IC, is the priority here.