Commodore 64 issue

[Celotine]

Got a new C64 and had to replace a marginal PLA. I did so with a modern reproduction not an original part. Everything seems to be cool now.. Except I can't seem to load games. Games either don't load or crash almost immediately. I'm using a disk drive emulator, not an original. I have a diagnostic/dead test cart. Dead test passes every time, diagnostic cart fails on ram test 1, freezes and doesn't finish. Ideas on what to do next?

[+OLD CS1]

8 hours ago, Celotine said:

diagnostic cart fails on ram test 1, freezes and doesn't finish. Ideas on what to do next?

Before getting to this part, I was thinking memory.  When the computer comes up, do you see the full amount of memory available in the BASIC header?

 

I am assuming, since you replaced the PLA, this is not a short-board 64C model.  It would be good to have a 64kx1 RAM chip (4164) to piggy-back onto RAM chips on the board, then run the RAM test.  It is likely to have a single RAM chip be flakey, less likely, though not impossible, for multiple chips to be bad.  Generally, piggy-backing a good RAM chip works.

[Celotine]

6 minutes ago, OLD CS1 said:

Before getting to this part, I was thinking memory.  When the computer comes up, do you see the full amount of memory available in the BASIC header?

 

I am assuming, since you replaced the PLA, this is not a short-board 64C model.  It would be good to have a 64kx1 RAM chip (4164) to piggy-back onto RAM chips on the board, then run the RAM test.  It is likely to have a single RAM chip be flakey, less likely, though not impossible, for multiple chips to be bad.  Generally, piggy-backing a good RAM chip works.

Ok I'll order some up soon. Need parts for my 5200 too. None of my ICs are socketed, I'm glad the piggyback thing works lol.