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CP4500 Stereo Bus Compressor / Re: No output on L-channel when engaged ("In" pressed) - right channel fine

« on: January 22, 2022, 01:35:10 PM »

Ok, the tread can be closed - I solved the issue. 

It was a misunderstanding from my side: I was trying to set up the second channel with only one expander cable. Now that I simply installed it to the 500 case it work perfectly! Just minor trimming - and it works great!

So to sum up: I had a broken soldering connection which I could locate with your help JPK. Thanks again! The second issue was my work understanding.

Now I can start working with it. And I will order a next kit immediately

2

CP4500 Stereo Bus Compressor / Re: No output on L-channel when engaged ("In" pressed) - right channel fine

« on: January 18, 2022, 04:22:43 PM »

Channel 2 steps 3 and 4:

Check if you also have any DC volts on TP7 and TP9. --> it reads -0.02 on TP7 0.00 on TP9 for step 3&4

What is the DC voltage (VDC) on pin 1 of U16 (white dot) in the 2 steps? --> -0.02 for both steps

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CP4500 Stereo Bus Compressor / Re: No output on L-channel when engaged ("In" pressed) - right channel fine

« on: January 17, 2022, 10:22:17 PM »

Great that helped me find a broken solder! I could repair it and and first channel now was easy to set up. Thank you!


However, it seem I have a second issue -now with the second channel. It is significantly louder than the first: 2 VAC on the Input and more than 3 on the output - even when IN not engaged/bypassed.


measurements: 

Channel 2, Step 3:
Signal level (VAC) on

• TP6=1.5VAC,
• TP7=1.5VAC, (2,5VAC)
• TP8=1.5VAC,
• TP9=0.06VAC (1,3VAC)

Signal level (VAC) on

• TP6=1.5VAC,
• TP7=0.4VAC, (2,5VAC)
• TP8=1.5VAC,
• TP9=0.2VAC (1,3VAC)

Any suggestion on where to start looking? I couldn't seem to find any flaw on PCB B. Could it be on PCB (c)?

Thank you so much for helping out!

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CP4500 Stereo Bus Compressor / Re: No output on L-channel when engaged ("In" pressed) - right channel fine

« on: January 17, 2022, 01:11:03 PM »

Thank you for the suggestion. However, the problem remains even after exchanging U7 & U17...

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CP4500 Stereo Bus Compressor / No output on L-channel when engaged ("In" pressed) - right channel fine

« on: January 15, 2022, 01:14:42 PM »

Hi there!

I am stuck in the setup. Here is the problem: No signal on left channel when engaged ("In" pressed") 

To be precise: there is a very low output readable/audible 

• Right channel works fine when "In" is engaged (PCB B)  - problem must be on PCB A
• Everything on the front panel works as expected (VU meter, LED, etc.)
• Soldering and component placement double checked
• There are only minor deviations in "In case your CP4500 doesn't work as expected" measuring procedure - especially on TP 2 & TP4 when small values were expected (step 6 & 7). However, my simple DMM might not be precise enough?

Photos and measurements: https://we.tl/t-YxjaN58oQD
Thank you so much for all recommendations or tests to find the issue!