Newly built kit left side no sound [resolved]

Ichibanwilliam · 1639

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Offline Ichibanwilliam

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on: August 27, 2021, 06:44:47 PM
Hello all!

  I just finished building my first SEX kit without previous kit building experience and the left side has no sound.
The event sequence goes:
1- Right after built up, no sound from left
2- touched up some solder joints and sound came back
3- removed headphone jack and pot to do some repaint
4- left side has no sound again

I checked the continuity from the RCA jack to the Pot and it looked fine. Made sure the RCA jack is not connected to ground with excessive solder and I touched up almost all of the solder joints (except for the ones that looked good to me). I used a 2A fuse in this build because I blew the 1A fuse and could not find a replacement that day  :P

My resistance and voltage were almost spot on except:
Resistance:
11. 671
25. 667
31. 108.1
32. 108.1
H5. 108.3

Thank you for your help in advance!

« Last Edit: August 31, 2021, 06:07:54 PM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: August 28, 2021, 04:52:16 AM
Is this no sound from both the headphone jack and the speaker terminals?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ichibanwilliam

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Reply #2 on: August 29, 2021, 01:10:17 PM
Is this no sound from both the headphone jack and the speaker terminals?

Thanks for replying PB. I do not have a pair of speakers. How can I test the speaker terminals?




Offline Paul Birkeland

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Reply #3 on: August 29, 2021, 04:03:45 PM
You can use a pair of clip leads on the speaker terminals and clip them onto the plug of your headphones. 

Based on what you've said, I would bet on a broken wire or loose connection on either the pot or around the headphone jack.  If you have trouble locating it, post a picture or the model number of your meter and I can help you trace signal through the amp.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ichibanwilliam

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Reply #4 on: August 29, 2021, 07:23:49 PM
I'm using Klein Tools MM700 as my DMM. I am not sure if I am making the connection correctly, please see the photo attached.
If I am making the correction correctly, then there's no sound coming from my speaker jack

Thank you!
Will



Offline Paul Birkeland

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Reply #5 on: August 29, 2021, 07:35:23 PM
One of your clips needs to go on the sleeve, which is the unoccupied bit of metal in your picture.

The Klein looks like it will measure low AC voltages, so that should be sufficient for signal tracing to see if things are dropping before they get into the amp or on the way out.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ichibanwilliam

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Reply #6 on: August 29, 2021, 07:58:57 PM
Got it. There is sound coming from the speaker jack. However, the left speaker jacks are much quieter. I need to almost max out the pot to get a decent volume.
We might be getting something here!!

Thank you,
Will
« Last Edit: August 29, 2021, 08:02:23 PM by Ichibanwilliam »



Offline Paul Birkeland

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Reply #7 on: August 30, 2021, 04:35:22 AM
The next test that you could do that is pretty simple is to temporarily solder in a jumper between the middle upper and middle lower lugs on the volume pot.  You can just reheat those joints and  poke a wire into each of the solder joints; the connection doesn't have to be great.

With that jumper in place, do you get both channels running?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ichibanwilliam

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Reply #8 on: August 30, 2021, 04:45:29 PM
I soldered the jumper in the pot as you instructed and there's sound coming from both sides. Assuming this means the problem comes from RCA to Pot?

Is it possible to have a bad pot? I actually have a new pot (audio note volume pot) arrived today that I was going to upgrade with C4S in a couple of months.
I can measure a resistance between RCA to ground. Does that mean the RCA is OK?

Thank you,
Will



Offline Paul Birkeland

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Reply #9 on: August 31, 2021, 06:36:10 AM
Hey, that's good news.  That does indeed just leave the wiring from the RCA jacks to the pot, or a solder bridge across one of the RCA jacks.

The pot can be damaged if too much heat and solder is applied and the solder sneaks its way into the pot. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ichibanwilliam

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Reply #10 on: August 31, 2021, 08:01:27 AM
Thanks! I will switch out the pot later today.

Meanwhile, do you happen to know if the audio note volume pot wires up the same way as the stock pot? There was no instruction or manual with my delivery.
I found a post here in 2015 saying that it is the same as the stock pot but I'm not sure if the info still stays true since the post was from 2015.

Thanks,
Will



Offline Paul Birkeland

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Reply #11 on: August 31, 2021, 09:31:04 AM
Yes, just hook it up the same way. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ichibanwilliam

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Reply #12 on: August 31, 2021, 04:30:51 PM
I installed the new pot but the same issue still exist. I did another experiment that I hope will bring some more info to the table:

Only the left RCA is connected to the amp.

When pot is at almost maxed out -> low volume at BOTH left and right side
When pot is maxed out -> Descent volume at left only

Pretty confusing...

Thanks,
Will



Offline Paul Birkeland

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Reply #13 on: August 31, 2021, 04:31:28 PM
Can you send me a link to the pot you bought...

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ichibanwilliam

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Reply #14 on: August 31, 2021, 04:32:46 PM
https://www.partsconnexion.com/ANVPOT-81914.html

Thank you so much for walking me through this!