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MU524 Vari-Mu Tube Compressor / Re: My Problems begin at step 6 of setup

« on: October 24, 2023, 11:30:51 PM »

After removing C12 and replacing it, I still get the same results. I did want to mention though, that once I dial in my 1k tone at 1.0VAC, and I switch the compressor on, it does increase the voltage slightly. Instead of a 3-4v increase, I get a .003-.004v increase. Since it's off by 1000, do I have a component value off somewhere?

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MU524 Vari-Mu Tube Compressor / Re: My Problems begin at step 6 of setup

« on: October 22, 2023, 05:26:05 AM »

Ok, I ran the tests you mentioned, and also double checked the transformer direction. The transformer was good, and I did not get any change in voltage after removing U4, and did not show any voltage across T3 and T4. That was with the front panel removed. I went ahead and ordered another C12 because I do have a pin that is very close to the capacitor. I believe the pin touches the capacitor so there's a good chance it could be damaged.

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MU524 Vari-Mu Tube Compressor / My Problems begin at step 6 of setup

« on: October 18, 2023, 02:40:19 PM »

Ok I'll try to keep it short, but I do want to include some other findings. I went through the troubleshooting guide before I posted just so some of the questions don't get redundant. But like the title says, my problems begin at step six. When I turn the unit on, I don't get the jump to 3-4v. It stays at 1v. I did go ahead and move forward, just to see what other numbers I got. I was able to get most of the voltages throughout the setup guide. If I remember correctly (it got late and my memory is foggy) I got to step 10 and was unable to get to the 3.6v. I ran out of turns on the TR4. I think one more voltage was off but I can't remember at the moment. Anyway, I got all the way to the end, and the input and output sections work just fine. I get gain up and down from both knobs, just no compression when turning up the input section, only gain. Where should I begin to look?


Edit:

Here are my test numbers

TP1 = TP2 41 VDC
TP1 = TP2 UNSTABLE
TP3 = TP4 0.51 VAC
OUTPUT = 1.032

TP3 0.23 VAC
TP4 2.86 VAC
TP5 2.61 VAC
TP6 -3.1VDC
METER -6db