Moog Music Forum

UPDATE:

Couldn't find the cause of the problems. Decided to take it to an experienced tech (Corey Davidson at Davidson Electronics). After tons of frustrating troubleshooting, he narrowed the problem down to the D/A converter. As original AM6012PC chips are quite expensive nowadays (around $60 for ...

UPDATE:

For those of you just joining us, here are my non-functioning Source's symptoms:
- No output when keys are pressed.
- Panel functions appear to be operating correctly.
- All power rail voltages are correct.
- The synth emits a quick "woop" sound upon turn-on (see below), but then only a ...

Thanks for all of the tips. I did a little investigation with my scope; perhaps one of you could enlighten me a bit on what I should be seeing. When probing the pins where I was told to expect a pulse stream, I saw what looked like square waves. But, when I pressed a key, those "square waves" (I put ...

Thanks for the information MC! I'll break out the scope, do some measurements, and report back. To this point I had just been using my Fluke 187. I have been, until now, unsure of when, exactly, the digital pulses were created.

Also, no voltage is detected at Pin 5 of U5 (Keyboard C.V.) on the Synth board when any key is pressed.

Hello again gentlemen,

An update:

- As a correction, R84 DOES have 5V on one side of it. Due to the lettering on the PCB being indistinct, I was reading the 2.4V off of R64, R67, and R66.

- Hint?: "Mod Rate" LED is solidly lit. It is not blinking. I've heard this may be an indication of CPU ...

Alright, alright. I know I phrased that a bit recklessly. :oops: I'm not as dumb as that comment appeared. :? The shorts I made weren't "random" in a true sense and weren't particularly dangerous. I simply injected small voltages (less than 5V) into a couple of the TL072s at points relatively ...

Yeah guys, I know the op amp shorting thing was not the best of all ideas.
I'll take all of your suggestions and try them out. Hopefully, I'll be able to report back with some positive info.

Thanks!

Dan

Hey everyone,

I'm new here, and I'm trying to learn a bit about my newly-acquired Moog Source. I'm pretty experienced with the electronics of amplifiers and other pro audio gear, but the multiple causes possible for my Source's problems is overwhelming. I'm hoping one of the experts here can help ...