You can isolate the vca by removing ic5 from its socket and bridging pins 1 and 8 with a 33k resistor. It´s too bad the datasheet is in japanese, but it´s possible to see it´s a bit like the ca3080; it´s an attenuator rather than an amplifier. If you bypass it with a piece of wire from pin 1 to pin ...

OK. If you lift r89, r72 and r74 the chorus will be isolated and you should definitely rule it out. Unless there´s some capacitive coupling caused by flux stains, a stray solder bridge or whatever, but that should have been already ruled out as well by this time. It´s like the first thing to check o...

A Lexicon MPX-1. Sounds beautiful.

Lost my reply. Later

No problem. OK, I was indeed thinking about clipping distortion, and was about to suggest testing the power rails near the opamps, decoupling caps and also the non polarized blocking caps, as any of those could cause asymmetrical distortion. Can you post an audio file? Is the distortion you hear pre...

Dont bother to replace the transistors. They are in the chorus audio path. I was being rethorical, or trying to.just take a more indepth look at the schematic. Two lines go from the output of the vca buffer: one goes to that filter where the transistors are and onto the bbd etc. Thats the wet signal...

If bypassing the chorus doesnt change the problem then the problem is not related to the bbd chips. It seems that it could be the final output stage, or the muting transistors, or any other thing in that area, but since the distortion is present at low final vca settings, its not in that area. It li...

IIRC on mine this fault it was caused by the hpf chip, IC3 on the chorus board. One voice sounded clean, two or more just distorted no matter what. A new CD4052 replaced the old one and the problem disappeared But it could be any other culprit in the signal path. On the main board there´s tp1 and tp...

See where it leads to. If it goes to one of the PCB´s mounting screws, and only that, there should be no trouble. It´s the only use I see for that third copper track (nr.2). It would be safer if the earth wire connected directly to the chassis via screw, nut and locking washer. But if the entire PSU...

http://i68.tinypic.com/72bwwm.jpg Just noticed that 3-pin connector in the second photo. In the schematic the central wire from the power cord leads to that connector and ends with a comb or trident like symbol. That´s the symbol for "chassis". See if there is a third copper track on the board lead...

Hey Alex. According to the schematic here on Version 1.1 the power cord green wire was connected to the chassis only. This should be "chassis, or safety ground". Usually it´s only a screw with self-locking washer near the mains wires. "Signal ground" is on the board and is provided by the center tap...

Except that they all got fined this year by the EU for collusion/ ant-trust, and producing poor quality capacitors due to their own cost cutting. Explains all of those "bad batch" incidents, like the disaster Apple had with the eMac. http://europa.eu/rapid/press-release_IP-18-2281_en.htm I find Far...

Well, I see a captive power cord. And what looks like an empty chassis. Did you install the cable yourself?
There is also a line voltage selector, which is good. Is it related to the 3 pin connector you mentioned?

And here is the output impedance of that industry standard that is the Minimoog :mrgreen: Audio Output Levels High Level Output Typical Voltage: 0.5 volts Maximum Voltage: 4.2 volts (peak-to-peak) Nominal Output Impedance: 3K Ohms :) Low Level Output (30 dB below High level) Typical Voltage: 15 mill...