Looking for a specific Oberheim Matrix-12 part

[Usabell]

Hi there! I'm still in the process of maintaining my Matrix-12, and solved some contact issues on the upper voice board recently that caused voice 6 to stop sounding. However, this caused a new problem when I turn the synth on. I now get hanging notes and sometimes the message "Voice 0 Processor Malfunction". I didn't do anything with the processor board, so I suspect the 40-pin flat cable to be the culprit here, especially since it feels like it might be easily broken (it's still the original from 1987 after all and shows signs of material wear). I'd like to try replacing this one, but couldn't locate a seller. Maybe someone here can point me in the right direction, thanks in advance. Right now I can't play this beautiful synth, which is really a shame!

[Roganation]

Hi champ. Have you made any headway into this? Sorry you're having problems but I also have the "voice 0 processor malfunction message" and wondered about a fix. Someone I spoke to mentioned:

If you have lost contact between the main CPU and both Voice cards, then my first port of call would be the clock connection from the main CPU end, perhaps the 3 pin connector has come loose or may be dirty on it's pins, a pencil eraser can help here.

Any bells ringing there?

Cheers.
JB

[Usabell]

Hi Roganation, I've tried replacing the voice processors today, but still get the same errors. I've also checked the three-pin connectors as you mentioned, but to no avail. At first I thought I might have put then in the wrong way until I realized that the middle pin is the signal and both outer pins are just ground. So there's no way to put them in "the wrong way". I will now just try to order the single parts to make such a cable myself. I still think it's the cable that is causing these problems. In the "Master" menu in the "Version" tab, I can see that it shows wrong version numbers for both voice boards. It shows "Main Software Version 1.1", "Cass 1.0", "Lower Voice 4.3", "Upper Voice 4.3". I know that I have the eeproms for version 1.4 in my synth, but if the replacement cable still doesn't work, I might need to look into that. Maybe the eeproms need to be changed (but I wonder why all of them went bad all of a sudden).

[Roganation]

Just seen this. Thanks for the reply and sorry you're still having problems. My malfunctions are fixed but now res and VCF fail tuning on voice 6.

Malfunctions were fixed with a system reset, which I am getting info together on in case it helps.

If I access page two on the tuning page and reset both voice 6s they then pass.

This ok or would you look to get it fixed?

Bests!
R

[Usabell]

Yeah, it's been some time, and in the meantime we tried making the new cable. After we made it, we soldered it to the processor board, and put the "outer" end on he upper voice board first. When we powered up the synth like this, it showed "VOICE 1 PROCESSOR MALFUNCTION", so we thought everything was fine and properly connected both ends to the two voice boards. We got the "VOICE 0 PROCESSOR MALFUNCTION" again, and never got back to the "VOICE 1 PROCESSOR MALFUNCTION" state, even after trying it out multiple times. Something was really screwed up with the synth.

Could you elaborate a bit on the system reset you did? Maybe I can try it out before bringing it in for repair.
My studio tech gave up on it already, as he realized he doesn't know enough about the way this synth boots up
He suspects the OS EPROMS to be faulty.

Right now I have an appointment with a professional synth repair expert in my country. His service is not cheap, but if he cannot fix it, no one can. But, if you could provide me with more info about the system reset, I would be more than happy!

Thanks in advance!

[kcqbd]

Hi Roganation,

I am having trouble finding information about how to do a system reset. Can you explain what you did?