Thursday, April 27, 2017

Oberheim Matrix-12 Synthesizer Power Supply Issues RESOLVED

In this video I show what I did to resolve my power supply issues on the Oberheim Matrix-12 analog synthesizer. Symptoms were intermittent non-boot, locking up, and the dreaded Voice 1 Processor Malfunction message. Along the way I'll talk about how the power supply works and how it is different than many synths from the era prior to this. Even though the Oberheim Xpander is a little different than the Matrix-12, its power supply works exactly the same. This may not enable you to fix your Matrix-12/Xpander completely, nor answer ALL questions you may have...but hopefully it will be helpful information.

YOU ASSUME ALL RISK WHEN REPAIRING YOUR OWN ELECTRONIC INSTRUMENTS! There's no shame in asking a friend for help or taking it to a reputable synthesizer technician. BE SURE TO UNPLUG THE SYNTH PRIOR TO DOING THIS KIND OF WORK.

0:00 Introduction
1:10 Getting Started
1:54 Dealing with an SMPS
3:16 Why did Oberheim use an SMPS?
3:40 Why I'm NOT going to troubleshoot this power supply
4:38 Power Supply Restoration and Results

Here are the Mouser parts numbers:
Power Entry Module - 871-B84771A0001A000
2W Shunt Resistors 0.1ohm - 667-ERX-2SZGR10V
sorry I don't have capacitor numbers, I did that work 2 years ago


Berode Analog-Synth said...
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Berode Analog-Synth said...

Hi G-Storm !

I had the same symptoms a while ago, mad function processor 1 etc ...

Looking carefully, I also had the two resistance crack
I was quick to change

I also wanted to change the filter, but I do not know how to connect the new

Could you confirm me how to connect the connections to the new filter

Theoretically the line that leaves the Fuse connect on the "Liner" and the other runs on the N

Could you please explain all this quickly to me please

Let me know