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

Timbucus · 30th Jan 2021, 11:46 pm

Looking at those traces it could be that the 244 is just having its output shorted by the 153 (E5) any of the ROMS or the 7425 (B2) but, it is driving just incredibly low which I know is a failure mode that Jerry has experienced a lot - and it needs a large fan out as it is driving more chips than the others. I don't suppose any of the 244's are socketed are they? So they can just be swapped over. I had a similar problem on my Triton (which does exactly the same with two 244's on the address bus incidentally) although in my instance it was on the inbound Keyboard which is also a 244.

30th Jan 2021, 11:46 pm	#377
Timbucus Octode Join Date: Mar 2019 Location: Barry, Vale of Glamorgan, Wales, UK. Posts: 1,363	Re: Non-working Commodore PET 3016 Looking at those traces it could be that the 244 is just having its output shorted by the 153 (E5) any of the ROMS or the 7425 (B2) but, it is driving just incredibly low which I know is a failure mode that Jerry has experienced a lot - and it needs a large fan out as it is driving more chips than the others. I don't suppose any of the 244's are socketed are they? So they can just be swapped over. I had a similar problem on my Triton (which does exactly the same with two 244's on the address bus incidentally) although in my instance it was on the inbound Keyboard which is also a 244.