Voltage Problems

Jcm0 · 1624

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Offline Jcm0

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on: March 05, 2023, 03:06:13 AM
My voltage check is giving wrong readings (mulimeter has DC volts selected); neither LED lights:

1 -275mv
2 -107mv
3 0
4 -106,5mv
5 -253mv

6 0
7 280mv
8 0
9 296mv
10 0

Thanks.



Offline Paul Birkeland

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Reply #1 on: March 05, 2023, 05:38:17 AM
Can your meter read a 9V battery properly? 

Can you post some build photos?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Doc B.

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Reply #2 on: March 05, 2023, 06:03:47 AM
Check to see if your fuse is installed properly and intact.

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


Offline Jcm0

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Reply #3 on: March 05, 2023, 01:43:10 PM
Can your meter read a 9V battery properly? 

Yes.

Can you post some build photos?

I tried but the forum won’t accept a “jpeg” extension, only “jpg”



Offline Jcm0

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Reply #4 on: March 05, 2023, 01:44:18 PM
Check to see if your fuse is installed properly and intact.

Yes, fuse is intact and installed correctly.



Offline Jcm0

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Reply #5 on: March 05, 2023, 01:50:36 PM
Here’s a photo.  My first time at this, so much sloppier than I’d like.



Offline Doc B.

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Reply #6 on: March 05, 2023, 02:50:39 PM
Is your 270 ohm 5w resistor connected at terminal 20 or 21? Also you really need to trim the excess leads on the terminal strips around the power transformer. Those long ends can short out and cause all sorts of problems.

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


Offline Paul Birkeland

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Reply #7 on: March 05, 2023, 03:03:49 PM
The long lead between B5 and B6 will cause tremendous problems if those two terminals touch. The LED at A3 needs to have its lead wrapped up and around the tube socket terminal before soldering. I can't see the soldering at A4, but it looks possibly suspect.  The wiring from the RCA jacks to the volume pot (which should be braided) is touching the green wires that heat the tubes, and this can lead to noise issues in the amp.

Doc found the reason all your DC voltages are 0V.

The UF4007 diodes are not installed as directed in the manual.

The bare tinned bus wire that leaves the safety earth lug by the IEC power entry module appears to be loose and not connected/soldered to where it's supposed to go.

The black wire going to power transformer terminal 15 needs to go under the 6 lug strip, not over it.

The white wire going to the headphone jack is improperly routed.

The wire leaving B2 and going up to terminal 2 should route under the terminal strip.

To make it easier to trim leads, the CHP-170 side cutters are inexpensive and widely available. 

Although this seems like a crazy long list, I think all of this could be addressed in well under an hour.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Jcm0

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Reply #8 on: March 05, 2023, 03:16:07 PM
The long lead between B5 and B6 will cause tremendous problems if those two terminals touch. The LED at A3 needs to have its lead wrapped up and around the tube socket terminal before soldering. I can't see the soldering at A4, but it looks possibly suspect.  The wiring from the RCA jacks to the volume pot (which should be braided) is touching the green wires that heat the tubes, and this can lead to noise issues in the amp.

Doc found the reason all your DC voltages are 0V.

The UF4007 diodes are not installed as directed in the manual.

The bare tinned bus wire that leaves the safety earth lug by the IEC power entry module appears to be loose and not connected/soldered to where it's supposed to go.

The black wire going to power transformer terminal 15 needs to go under the 6 lug strip, not over it.

The white wire going to the headphone jack is improperly routed.

The wire leaving B2 and going up to terminal 2 should route under the terminal strip.

To make it easier to trim leads, the CHP-170 side cutters are inexpensive and widely available. 

Although this seems like a crazy long list, I think all of this could be addressed in well under an hour.

Thank you very much.  I knew I must have made many mistakes.  My first time without a PCB.  I’ll address all this (and Doc’s observation).



Offline Deluk

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Reply #9 on: March 06, 2023, 02:49:21 AM
Cutting lengths for all of the wires are in the manual to help you. I found them all to be good except the black/white/red from the inputs to the volume control. Because I braided the wires very tight it made them a fraction short for easy attachment to the volume control. Cutting them all about 3/4" longer would give a bit more wriggle room for the ones that needed it.
I hope the team solve your problems. Happy listening.