Author Topic: Setup Help THRESHOLD potentiometer counter clockwise reduces the out ?

March 22, 2021, 07:21:46 am
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Jason

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Adjust the signal amplitude from the DAW in order to read 3.0 VAC on the DMM. Done

Check that turning the THRESHOLD potentiometer counter clockwise reduces the output level.  level doesn't reduce ? 

Check that turning the MAKEUP potentiometer clockwise increases the output level. Makeup gain works fine. 


Adjust trimmer T1 in order to get absolutely no output level change when switching on and off with the IN switch. Done



March 22, 2021, 10:10:28 am
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JPK

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March 22, 2021, 05:43:29 pm
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Jason

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TP 4 has voltage passing through 14.94
TP 13 stays on -14.6
« Last Edit: March 22, 2021, 05:45:59 pm by Jason »

March 23, 2021, 05:18:26 pm
Reply #3

JPK

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Quote
TP 4 has voltage passing through 14.94
On which test step? AC or DC?



Quote
TP 13 stays on -14.6
From the schematic, you can see that TP13 is made by U21, P1, R95...R99.

Check the value, direction and solder joints of these components.

JPK

March 24, 2021, 07:05:24 am
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Jason

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March 24, 2021, 07:19:29 am
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Jason

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I have a feeling it could be the IC's, I've ordered some new ones 

March 25, 2021, 08:18:11 am
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JPK

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Did you need to unsolder some component during the build?
In such a case check that the vias that connect the top and bottom pads together are still there.
Can you report the DC values you read on each pin of U21?
JPK

August 29, 2021, 01:44:26 pm
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Philipp

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Hi,

I got board REV1.3.

I have the same issue: Level does not decrease with Threshold control.

I did the voltages check. On step 4, TP13 does not show any DC, no matter where I have the pot. The pot itself seems fine. Also checked the components U21, and R95...R99. Direction, values and joints seem fine.

What should I check next?

Thanks and regards,
Philipp

August 29, 2021, 03:11:19 pm
Reply #8

Philipp

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Dc Voltages at U21 pins with Threshold at +15 and makeup at 0 and 0 input:

1,2,3,7,8: 0V
4: -15.9V
5: +16V
6: +2.9V
« Last Edit: August 29, 2021, 10:08:58 pm by Philipp »

August 30, 2021, 05:24:13 pm
Reply #9

JPK

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Are you numbering the pins like this?
Pin 8 should be +16V
JPK

August 30, 2021, 10:20:11 pm
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Philipp

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Sorry, had 5-8 reversed.

So:
1,2,3,5,6: 0V
4: -15.9V
7: +2.9V
8: +16V


September 01, 2021, 05:34:12 pm
Reply #11

JPK

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Quote
On step 4, TP13 does not show any DC, no matter where I have the pot.


Quote
7: +2.9V
TP13 and U21 pin 7 are connected together. Find out why the connection is broken.
JPK

September 01, 2021, 11:59:50 pm
Reply #12

Philipp

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Hi Jean-Pierre,

thanks for the hint. Turns out the problem was with the test pins. Once I applied solder from the top, everything works as it should.

On this build either the pins were bigger or the holes smaller. I remember them sliding in easily on the mp573 and cp5176. This time I actually had to widen the holes a little to get them even in. Maybe there was not enough space for the solder to flow through to the top side.

Maybe this is of help for others.

What a fantastic sounding unit! Makes me regret having spent money on plugin compressors.

Thanks,
Philipp


September 03, 2021, 05:38:33 pm
Reply #13

JPK

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