Volume Control not working

hpleung · 1993

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Online Paul Birkeland

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Reply #15 on: January 12, 2022, 01:02:34 PM
What is the resistance between the upper outer pair of lugs on the volume pot?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline hpleung

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Reply #16 on: January 12, 2022, 01:59:35 PM
So between the upper outer pair of lugs of the volume pot, the resistance is 96.2kohm.



Online Paul Birkeland

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Reply #17 on: January 12, 2022, 02:09:04 PM
What is the resistance between the upper outer pot lug and the shell of the left RCA jack?

What is the resistance between the upper inner pot lug and the center pin of the left RCA jack?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline hpleung

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Reply #18 on: January 12, 2022, 03:22:39 PM
I am assuming left RCA jack means the RCA Jack where the red wire is connected. This is using the orientation as per the manual.

What is the resistance between the upper outer pot lug and the shell of the left RCA jack?

96.4 kohm

What is the resistance between the upper inner pot lug and the center pin of the left RCA jack?

91.6 kohm



Offline Doc B.

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Reply #19 on: January 12, 2022, 03:33:36 PM
red - right

white - left

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Online Paul Birkeland

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Reply #20 on: January 12, 2022, 03:39:35 PM
You have some situations that are looking paradoxical.  I don't suppose you might have a loose black wire on your headphone jack?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline hpleung

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Reply #21 on: January 12, 2022, 04:35:19 PM
Using left is white wire.

What is the resistance between the upper outer pot lug and the shell of the left RCA jack?

96.5 kohm still

What is the resistance between the upper inner pot lug and the center pin of the left RCA jack?

Its also 96.5 kohm

I do not see any loose black wire.

I am going to do another pass at re-soldering all the connections.






Online Paul Birkeland

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Reply #22 on: January 12, 2022, 04:47:12 PM
Using left is white wire.
What is the resistance between the upper outer pot lug and the shell of the left RCA jack?
96.5 kohm still
What is the resistance between the upper inner pot lug and the center pin of the left RCA jack?
Its also 96.5 kohm
I noticed my red RCA center pin has 90.7 kohm but my white RCA center pin has OL resistance. I believe this is also supposed to be 90.7 kohm. Wanted to confirm this - note this has the speedball upgrade.
These conditions should be able to happen at the same time.  Can you recheck the resistance between terminal 12 and the center pin of the left RCA jack?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline hpleung

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Reply #23 on: January 13, 2022, 08:22:52 AM
Hi,

So, I resolved the issue and the Crack is back to working and sounding excellent as it was. My apologies for taking so long on this and thanks for the support along the way.

Yesterday, I reinspected all connections and resoldered any connection that looked remotely suspicious. In particular, I removed all the solder from my potentiometer (from all lugs) and started from scratch. At this point, I think what contributed to the issues in this long thread is poor soldering of the potentiometer. It is a good learning because when I looked at the soldering prior to this, it looked fine to me but clearly there was still some issue.

Still got a question though - The crack sounds good.

However, when I measure the resistance from 12U to the Middle of Red RCA Plug is about 96.5kohm.

The same value for the White RCA Plug is about 92.5 kohm.

They are a bit different - is that ok or does that mean the potentiometer is slightly damaged from all this resoldering? Sonically, I cannot tell.

Thanks.


 



Offline Doc B.

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Reply #24 on: January 13, 2022, 08:35:30 AM
That difference is pretty typical, and not a big deal.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.