StickyRice
Member
I found a 2001-8 BS in a rubbish skip and remembering them from my youth decided to take it home and see if it worked.
Well of course it didn't , it had just one line of random characters in the centre of the screen.
It has 2114 RAM and 6540 ROM chips with a 320132 system board.
I built Stephan Slabihoud's Retro Chip Tester which I have found super useful in fault finding this PET.
It showed I had several faulty TTL chips in the video circuit, 10 bad 2114's and 4 bad 6540's in H3,H4,H6 & H7.
I replaced the bad TTL, RAM and now get a full screen of random characters.
Next I ordered some 6540 to 27C64 adapter boards from Retro Innovations. Built and installed them but still get same full screen of random characters.
I probably have others failing chips not located yet BUT I am unsure if I have configured the adapters correctly.
I have concatenated the 2k ROM images four times and burnt the 8K 27C64's EEPROMS.
Should I use all 5 resistors for a 27C64? Can I have a mixture of original 2K ROMs & these adapters with 27C64 8k EEPROMS in H1 to H7?
If anyone has used these in the past or can guide me in the right direction I would be grateful. I would love to get this machine working again.
Daniel
Well of course it didn't , it had just one line of random characters in the centre of the screen.
It has 2114 RAM and 6540 ROM chips with a 320132 system board.
I built Stephan Slabihoud's Retro Chip Tester which I have found super useful in fault finding this PET.
It showed I had several faulty TTL chips in the video circuit, 10 bad 2114's and 4 bad 6540's in H3,H4,H6 & H7.
I replaced the bad TTL, RAM and now get a full screen of random characters.
Next I ordered some 6540 to 27C64 adapter boards from Retro Innovations. Built and installed them but still get same full screen of random characters.
I probably have others failing chips not located yet BUT I am unsure if I have configured the adapters correctly.
I have concatenated the 2k ROM images four times and burnt the 8K 27C64's EEPROMS.
Should I use all 5 resistors for a 27C64? Can I have a mixture of original 2K ROMs & these adapters with 27C64 8k EEPROMS in H1 to H7?
If anyone has used these in the past or can guide me in the right direction I would be grateful. I would love to get this machine working again.
Daniel