Diagnostic cart 586220 and tests ?
Posted: Thu Sep 28, 2017 8:45 pm
I now have a diagnostic cartridge 586220 which seemed like a tool I'd need for my C64 resurrections.
But am having an issue straight away ...
I popped it in my main C64 ..and let it run ..
Zero page OK
Stack page OK
Screen RAM OK
but the test hung at RAM TEST1 ?
So ..thinking it might be me ..or the cartridge tried it in another C64 ..
There were errors but the test continued ..(I dont have a harness)
RAM test 1 OK
RAM test 2 OK
So ..figured there _must_ actually be a fault on the first C64
luckilly I had fully chip based the RAM chips
U9 > U12 and U21 > U24 (8 x OKI 3764-15RS) ...so swapped them out one at a time ..
Still the test hung ..
Next I figured ...swap out the 2x 74LS257.
These were also swapped out one at a time ..
still the test hung at the same point ?
Is it possible this cartridge doesn't work with all C64 pcb variants
This one is a 250425 1984 ..made in HK
OR ..is there a possibility this fault might lie else where ..and not the RAM ..
I could start randomly swapping out chips ..but I thought it best to seek advice first..
rgds
VS
But am having an issue straight away ...
I popped it in my main C64 ..and let it run ..
Zero page OK
Stack page OK
Screen RAM OK
but the test hung at RAM TEST1 ?
So ..thinking it might be me ..or the cartridge tried it in another C64 ..
There were errors but the test continued ..(I dont have a harness)
RAM test 1 OK
RAM test 2 OK
So ..figured there _must_ actually be a fault on the first C64
luckilly I had fully chip based the RAM chips
U9 > U12 and U21 > U24 (8 x OKI 3764-15RS) ...so swapped them out one at a time ..
Still the test hung ..
Next I figured ...swap out the 2x 74LS257.
These were also swapped out one at a time ..
still the test hung at the same point ?
Is it possible this cartridge doesn't work with all C64 pcb variants
This one is a 250425 1984 ..made in HK
OR ..is there a possibility this fault might lie else where ..and not the RAM ..
I could start randomly swapping out chips ..but I thought it best to seek advice first..
rgds
VS