BrainStruck
Member
Good evening, day or morning all,
I have a Commodore PET 2001-8 that's giving me some trouble. When I first got it, I couldn't get it to boot at all. It would give me a semi-random screen. After removing all of the chips, cleaning the system board and spraying all of the chip sockets with Deoxit, I reinstalled all but PIA 1, PIA 2 and all memory except for the I1, I2, J2 and J2. At this point the system would boot to the Ready prompt. I cycled through all of the RAM chips and found one defective so it's now running on all but the last 4 chips. I reinstalled PIA 2 (MOS 6522) and it boots to a Ready prompt, but no keyboard. I install PIA 1 (MOS 6520) and it hangs at the random character screen. I read that the MC68521 was a modern replacement for the 6520 so I ordered 1 (well minimum of 10 per order - anyone need any?) and it still hangs at the random character screen.
I'm not sure what the troubleshooting procedure is from here. I do have a multimeter and oscilloscope. Can someone please point me in a direction to go next?
Thanks in advance!
Brian
I have a Commodore PET 2001-8 that's giving me some trouble. When I first got it, I couldn't get it to boot at all. It would give me a semi-random screen. After removing all of the chips, cleaning the system board and spraying all of the chip sockets with Deoxit, I reinstalled all but PIA 1, PIA 2 and all memory except for the I1, I2, J2 and J2. At this point the system would boot to the Ready prompt. I cycled through all of the RAM chips and found one defective so it's now running on all but the last 4 chips. I reinstalled PIA 2 (MOS 6522) and it boots to a Ready prompt, but no keyboard. I install PIA 1 (MOS 6520) and it hangs at the random character screen. I read that the MC68521 was a modern replacement for the 6520 so I ordered 1 (well minimum of 10 per order - anyone need any?) and it still hangs at the random character screen.
I'm not sure what the troubleshooting procedure is from here. I do have a multimeter and oscilloscope. Can someone please point me in a direction to go next?
Thanks in advance!
Brian