Sound Skulptor forums
Build help and troubleshooting => CP5176 FET compressor => Topic started by: DUYBuilder on October 11, 2023, 11:17:27 PM
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I'm using a CAPI module extender to test this with my 500 series rack. It passes a sine wave in bypass mode, but nothing when engaged. Used leaded solder with no additional flux.
Here are my voltage measurements with pictures.
2. Check the DC voltages:
First check the supply voltages as described in the setup guide. - All check out
Check you get no DC volts at the output of the DOA on L1 top pin. Any DC above a few millivolts here shows that there is an issue with your DOA. .- .23 v DC
Next, without any input signal, connect the voltmeter black probe to the 0V pin and note the DC voltages you get at the points shown on the attached picture. Compare with the expected results (more or less 10%).
A: 12.5V
B: -.588V
C: 13.13V
D: -.02V R11
E: 14.89V
F: -.788V
G: -14.8V
(https://lh3.googleusercontent.com/3qZsUnFU3gHB-zP269bsucHyrtZ7Lr5ukkegSmItXNUThJwqElZacXjclypVaOsf1rShqbVe3YxJyLBv3GV2oqpD8cjJd1HK_hW4J3CD0Gqa_N0-5leMv8gAQtDgxXH7P-GfGmempWBAwz44qdU6og)
3. Try to follow the signal - no signal from TP1, 2, or L1.
(https://i.ibb.co/gjW843q/IMG-20231011-140911137-HDR.jpg)
(https://i.ibb.co/3sTfNtn/IMG-20231011-140926461.jpg)
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In passing audio should i be looking at AC or DC on the test points? I'm assuming DC.
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Check the value of R15, R14, R9 (by color code).
Check the direction of C12, C11, C6.
Try to follow the signal in TP1, TP2, L1 top pin.
The DMM must be set to AC volts. The voltage you read must vary with the position of pot P1.
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Check the value of R15, R14, R9 (by color code).
Check the direction of C12, C11, C6.
Try to follow the signal in TP1, TP2, L1 top pin.
The DMM must be set to AC volts. The voltage you read must vary with the position of pot P1.
Thank you. All parts double checked and they are correct. Still no AC voltage between TP1 and 0V.
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Check the solder joints on transformer T1.
Check the solder joints on connectors CN3a and CN3b.
Check if you can measure the input signal between the 2 side pins of pot P1.
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Check the solder joints on transformer T1.
Check the solder joints on connectors CN3a and CN3b.
Check if you can measure the input signal between the 2 side pins of pot P1.
Ok, I think I see the issue. I'll need to replace CN3. Is there a part number for the plug (male) connector?
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Part number: H2RA-20-UA
https://www.digikey.com/en/products/detail/adam-tech/PH2RA-20-UA/9830622?s=N4IgTCBcDaIAoAkwCUCCBaMAGdBVVIAugL5A
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Part number: H2RA-20-UA
https://www.digikey.com/en/products/detail/adam-tech/PH2RA-20-UA/9830622?s=N4IgTCBcDaIAoAkwCUCCBaMAGdBVVIAugL5A
Thank you.
I'm stuck on step 7.
I'm using: Abelton Live to play your sin file via a Presonus interface via USB. That goes into a Lindell Audio interface with no other modules in it, and the 5176 is extended out of the Interface. With max Abelton gain and volume from the presonus, I'm only able to register 2.8V AC on my fluke meter.
(https://i.ibb.co/p4pnPyL/IMG-20231125-164056026.jpg)
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Do you get the correct DC voltages now in points A to G?
With 100mVAC at the input, do you get
- 100mVAC at the output in bypass?
- 73mVAC on TP1 against 0V?
- 1.4VAC on TP2 against 0V?
- 8VAC on the top of L1 against 0V?
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My sincere apologies. I misunderstood how the unit worked. I thought that the green LED indicated that it was bypassed. With the Green LED on I can get more than 13.5V. I am proceeding with calibration.
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Thank you for your help. I calibrated all modules up to the final step, as i was in my workshop with a poor audio interface. All but one were great, and the one that is bad has a bad DOA (separate forum thread).
I tested the other five today in the studio so I could monitor the low end and distortion settings. Audio on the five were great, but two now have no VU metering with the compressor engaged or not. All units had working vu sections that I calibrated the night before. Have you ever come across this?
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Do you hear compression on the units with no metering.
Check that the Input and Out potentiometer pins do not touch the meter board (pins must be cut very short on the meter board).
Other than that, I can only think of a bad connection somewhere.
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Yes, there is compression, just no metering. I am able to see LEDS light up and can calibrate in step 10, with both jumpers installed.
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Try installing a working meter board from another unit to know which board the issue comes from.
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Ok that's sorted.
With the exception of the unit with the bad DOA in the other thread, the others are great with one exception wherein the link switch doesn't work. It won't click in.
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Check that it is not blocked by the face plate. Sometimes, simply untightening / retightening the front PCB screws solve the problem.
If the switch is really unfunctionnal, contact us for a replacement.