driver testing [resolved]

joralieu · 2024

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Offline Paul Birkeland

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Reply #30 on: May 09, 2024, 04:17:44 PM
There's a terminal labeled "X" on the PC board, can you measure the DC voltage on that pad on the side where you have 15V at Kreg?  Also it wouldn't hurt to just swap the 5670 tubes to be extra sure this isn't something that's tube related, though that seems quite unlikely under these circumstances.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline joralieu

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Reply #31 on: May 09, 2024, 04:31:35 PM
I get 2.9V at X I have swapped the tubes and it made no difference



Offline Paul Birkeland

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Reply #32 on: May 10, 2024, 04:55:23 AM
Fundamentally this may have a lot to do with the 2.49K and 249K resistor swap.  You could try replacing the 431 regulator there, and that might work, but you may also just have an iffy joint or a lifted trace on one end of the 2.49K resistor on that side of the board.  I would probably pop in a new regulator and add a little heat and solder to the 2.49K resistor.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline joralieu

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Reply #33 on: May 10, 2024, 12:45:33 PM
I reheated the 2.49k resistor and everything measures right now. Sheesh I knew it was something simple.
Thanks
Joe



Offline joralieu

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Reply #34 on: June 11, 2024, 12:07:16 PM
Ok, I finally got the hooked up and still have a problem. The left channel is significantly lower output than the right with the trimpots turned all the way up. Would this be a problem with the driver board? I have switched tubes and cables around and the left side remains low.



Offline Paul Birkeland

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Reply #35 on: June 11, 2024, 12:28:38 PM
Are the DC voltages consistent between channels?  Most of the time when we see something like this, it's an issue with output transformer wiring if everything else is equal between channels.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline joralieu

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Reply #36 on: June 11, 2024, 12:45:09 PM
They were but maybe something may have happened since. I will check again which ones should check first?



Offline Paul Birkeland

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Reply #37 on: June 11, 2024, 05:18:41 PM
You can post some build photos, concentrating on the areas around the output transformers.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline joralieu

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Reply #38 on: June 12, 2024, 04:33:48 PM
All is good now. I had the black wire on the left side  output transformer soldered to terminal 1 should be 3.
Thank you