[230bpm]

Hello, i just finished building my first CP4500. I was able to assemble the unit without any problem and also did the Setup and calibration for the first channel, all according to the guides provided on the website. However as soon as i install the board for the second channel (Board C) and i activate the "IN" button the VU Meter instantly slamms hard to 20dB of compression, regardles of any signal being send to the unit.

With board C not connected the unit works and sounds great, all buttons and all setting work on the first channel, so hopefully there is no issue with board B.

With board C connected and the unit bypassed ("IN" Button depressed) the signal passed through without problems. Same as for "IN" Button pressed an Mix set to 100%. However the VU Meter shows 20dB compression and no audio passes through (not even the first channel wich worked fine without board c installed). Even with the signal boosted (+20 makeup) no singal is coming from the unit.

I did check the Test Pins on board C and i get around 1.5 on T6 and T8, however T7 has a readout of 0, same for T9 (however my DMM might not be sensitive enough to register <1V.

So far i checked all my solder joints, resoldered some that didn't look to great, and i switched U16 and U20 in case there is something wrong with those ICs, however nothing has changed. Hopefully you guys can help me get this Compressor to work!

Below two Pics of Board C:

https://www.dropbox.com/s/wc0twpprwxdth72/DSC_4052.jpg

https://www.dropbox.com/s/ljma27zgt0xcfym/DSC_4053.jpg

Best Regards,

Jan

[JPK]

Please measure the DC voltage on TP10.

[230bpm]

DC voltage on TP10 is around -12.7V with both "in" button pressed and depressed.

[JPK]

There is an issue there.
Check the value, solder joints and direction of
D2, D13 to D17, R14 to  R18, R85 to R88, L2, RSW1, U18, U20.
Can you report the DC voltages on U20 pins 1, 2, 3 and U18 pins 5, 6, 7.