PROPHET64 & MSSIAH Userforum

dJ dAb · 2012-02-14 05:39:27

I currently have quite a few old C64's laying around and all of them work with the Mssiah cart but for some odd reason mine trusty 64C wont work properly. For some reason, any time I load a song into the sequencer it crashes... not just from disk but even the demo causes it to crash. I've adjusted the contacts to a firmer grip, cleaned the contacts, swapped kernal rom, and even re-soldered all cartridge solder points (kinda a last ditch effort) and still it will not work! One last important thing.... My sid chip is faulty. Could a faulty sid chip be causing these problems?

btw... I've had this 64C since the late 80's and it the smaller version of the pcb w/ 8580 sid... a keeper.

Thanks, Sean

dJ dAb · 2012-02-14 05:41:05

Oh yeah, I'm currently waiting to get a replacement 8580 sid.

dJ dAb · 2012-02-16 21:35:04

Received another faulty 8580 SID (HP, BP & LP all bad... Argh!) but I did get my cartridge problem resolved by replacing the 8500 microprocessor chip.

beltonaki · 2012-03-05 12:35:03

dJ dAb wrote:
Received another faulty 8580 SID (HP, BP & LP all bad... Argh!) but I did get my cartridge problem resolved by replacing the 8500 microprocessor chip.

Hi there dJ dAB,

I too have the C64C since way back when. My C64C won't run the banks test though (and apps only occasionally).

Did the banks test do okay with your C64C before you aimed for switching the 8500? What does the 8500 do and why did you end up replacing it?

dJ dAb · 2012-03-06 20:05:06

I did get mine to work but I did so by testing 2 64Cs side by side. I pretty much, patiently, toubleshooted by swaping chips.. one at a time from the working machine to the non-working machine until I found the suspect chip. In my case it was the 8500. Now everything runs smooth and luckily when swapping these chips both machines actually work so it could very well be that it was a minor issue with that chip or it wasn't seated right.

Other then that, the test banks did work... except for the issue I was having with bad filters on my sid chip. So, I doub't our problem are related but I would suggest swapping some chips from a working machine to pin point the problem.

On a side note, I do still have a problem oocassionally but, I've found it also depends on what power supply I use. Maybe one chip was more prone to the issue because of a slightly lower voltage coming from the psu.

Good luck.

Last edited by dJ dAb (2012-03-06 20:06:18)

PROPHET64 & MSSIAH Userforum

#1 2012-02-14 05:39:27

Cartridge slot problem on a 64C w/ faulty 8580 sid.

#2 2012-02-14 05:41:05

Re: Cartridge slot problem on a 64C w/ faulty 8580 sid.

#3 2012-02-16 21:35:04

Re: Cartridge slot problem on a 64C w/ faulty 8580 sid.

#4 2012-03-05 12:35:03

Re: Cartridge slot problem on a 64C w/ faulty 8580 sid.

dJ dAb wrote:

#5 2012-03-06 20:05:06

Re: Cartridge slot problem on a 64C w/ faulty 8580 sid.

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