[sdiy] Problematic Moog Opus 3

[Brain Dekork]

I saw this ring modulator effect on a CS-60.  Same type of thing - it happened at random times.  It turned out to be bad filter caps in the power supply, so the 60Hz signal would get coupled into the control lines.  I would replace those caps first (the big ones).
 
Brian

Chad Coffman <chadcoffman at comcast.net> wrote:
So, I just got this Opus 3, right? The problem, as advertised by the seller...
 
"I have had the brass and organ sections working, but other times they sound like something ran through a weird ring modulator. I don't think the string section ever worked. Articulator 2 mode never seemed to work, but I could never figure out what it was supposed to do anyway".
 
Since I've had it (a few days), the Brass and Organ sections seem to be right on. No problems. The Strings section also works without any problem. However, two problems do appear...
 
First, anything that I put through Chorus (Strings or Organ), there seems to be a one-second delay. It's as if the attack is at full-level.
 
Second, Articulator Mode 2 doesn't seem to work, as mentioned by the seller.
 
I'm going to open the unit up later in the week to refinish the wood sides and clean the Black Ooze from the switches. I'm pretty sure I can determine the problems with Chorus and Articulator Mode 2, but I'm a bit pessimistic about fixing the problems described by the seller (no strings, brass/organ "ring modulator"), since I cannot verify their existence.
 
My question is, does it make sense that the problems described by the seller are different than the problems experienced by me? I've read reports online about Opus' with these same problems, but no solutions. Any tips or solutions would help.
 
**BONUS QUESTION**
 
I may as well replace the capacitors while I have the unit cracked open. This will be a new experience for me. Can I replace the capacitors with new ceramic ones?
 
**EXTRA BONUS QUESTION**
 
Where is the service manual?!
 
 
As always, many thanks in advance.
 
 
Chad 

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