per
Veteran Member
I recently got a 1985 breadbin C64, and it's giving me the black screen on boot.
From what I've read, a whole lot of things can go wrong and give a black screen. I've tried to eliminate a few things, and it seems like I might be in luck. I'll not get my hopes completely up yet though.
1. The voltages are OK (tested both AC and DC) allthough the PSU plastic case is *slightly* deformed by heat.
2. Power LED comes on, so the system is receiving power and not screwing it up.
3. When turned on, there is some brief activity on the disk drive. A sign of life, so maybe the CPU might be able to reach the ROM kernel?
I suspect a bad RAM chip, but I'd love some more input from C64-experienced people on this.
PS. This one is the big-board version, using regular TTL instead of custom chips as glue logic.
From what I've read, a whole lot of things can go wrong and give a black screen. I've tried to eliminate a few things, and it seems like I might be in luck. I'll not get my hopes completely up yet though.
1. The voltages are OK (tested both AC and DC) allthough the PSU plastic case is *slightly* deformed by heat.
2. Power LED comes on, so the system is receiving power and not screwing it up.
3. When turned on, there is some brief activity on the disk drive. A sign of life, so maybe the CPU might be able to reach the ROM kernel?
I suspect a bad RAM chip, but I'd love some more input from C64-experienced people on this.
PS. This one is the big-board version, using regular TTL instead of custom chips as glue logic.