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MU524 Vari-Mu Tube Compressor / Re: Step 8 in the calibration instructions

« on: May 17, 2024, 11:24:38 PM »

Ok, a little embarrassing.... I took the board off of the bracket to check for bad solder joints, and the damn foam piece thats used to ship the ICs was stuck to the back of the pcb. I checked it to see if it was conductive, and sure enough it was. I put the compressor back together and it calibrated perfectly. Now on to the pres 

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MU524 Vari-Mu Tube Compressor / Re: Step 8 in the calibration instructions

« on: May 17, 2024, 10:35:41 PM »

Thanks for the quick response! I went off of the printed out BOM which shows TR1 as 203, but there is a vertical line running through the text. Maybe it just looks that way, my mistake. I tested the compressor after I made my post, and although it worked, it was very noisy. I'm going to check the parts you listed and try to recalibrate. I'll report back.

Thanks again!

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MU524 Vari-Mu Tube Compressor / Step 8 in the calibration instructions

« on: May 17, 2024, 03:34:22 AM »

Hi, I am having issues with the last part of stem 8. I am unable to zero out the voltage using TR1. The marking on the variable resistor doesnt match the BOM. It reads 202 while the BOM says 203. I'm assuming that this is my issue. The other Vari-mu that I purchased, shipped with the same variable resistor (202 instead of 203). I havent calibrated that one yet, but I'm about to to see if I get the same issue. Anyone else have this issue, isnt even that important? I can get it down to 2.3v, but thats it.

Thanks