Sound Skulptor forums

Build help and troubleshooting => CP554 Diode bridge compressor => Topic started by: JPK on August 18, 2023, 11:49:03 AM

Title: In case your CP554 doesn't work as expected
Post by: JPK on August 18, 2023, 11:49:03 AM
Check the usual suspects:
Forgotten solder joint,
Bad solder joint (reflow suspicious joints),
Reversed components (transformer,s electrolytics, diodes, transistors, IC's). In case of IC's, probably destroyed, better replace,
Flipped IC's or transistors,
Trim all the component leads and test pins as short as possible. Nothing must touch the chassis plate.


Check the DC voltages:
Check the supply voltages as described in the setup guide.

Check the side chain:
Set the compressor as described in step 9 of the setup guide.
Remove the jumper on JMP1.
Inject a 1VAC sine signal into the input.

Threshold switch position     TP4 & TP5 AC voltage    JMP1 pin1 DC voltage
+6dB    0.11V    0.14V
  0dB    0.22V    3V
-6dB    0.45V    10.8V
-21dB    2.4V    15V