UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Just got myself a commodore pet setup but not working

SiriusHardware · 13th Jun 2022, 5:33 pm

I did once find -a- PET monitor component layout which included what was supposed to be a transparent 'mask' showing the PCB tracks as though looking at them through the PCB but someone had managed to get the track overlay reversed east-west, so the LOPT was in (say) one of the upper corners and its PCB pads were in the opposite upper corner. Completely useless.

That's why that find by Colin is so vital, it is exactly what we needed in order to be able to indicate where to take the readings from.

I appreciated your work in summarising the places to measure from on the topside but I think access to those points with a scope probe with the PCB in situ would be very difficult with the tube and scan coils overhanging, you really would have to undo the board and slide it out and maybe fix it to the rear posts through the front holes to stop it from wandering off. That's not something I would have been comfortable asking Pud to try at this stage.

13th Jun 2022, 5:33 pm	#83
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,569	Re: Just got myself a commodore pet setup but not working I did once find -a- PET monitor component layout which included what was supposed to be a transparent 'mask' showing the PCB tracks as though looking at them through the PCB but someone had managed to get the track overlay reversed east-west, so the LOPT was in (say) one of the upper corners and its PCB pads were in the opposite upper corner. Completely useless. That's why that find by Colin is so vital, it is exactly what we needed in order to be able to indicate where to take the readings from. I appreciated your work in summarising the places to measure from on the topside but I think access to those points with a scope probe with the PCB in situ would be very difficult with the tube and scan coils overhanging, you really would have to undo the board and slide it out and maybe fix it to the rear posts through the front holes to stop it from wandering off. That's not something I would have been comfortable asking Pud to try at this stage.