Voltage check [resolved]

pancho · 1576

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Offline pancho

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on: November 17, 2018, 05:27:19 PM
Voltages measure as follows

1-162
2-109
3-0
4-110
5-58
6-0
7-147
8-0
9-83
10-0

LED from center to front pin not lit

Thanks in advance

« Last Edit: November 18, 2018, 08:10:09 AM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: November 18, 2018, 05:26:42 AM
1-162
2-109
This is really only a possibility if you have a loose solder joint along the buss of black wires winding its way from the power transformer to the headphone jack, then over to terminal 3. 

As far as the LED on pin A3 not being lit, the voltage at terminal 5 suggests that there is conduction here, so that is inconsistent (and also points to a loose ground wire).

The most common loose ground wire is where the black wires meet at the headphone jack.  It's pretty easy to solder one to the jack and have one that's just loose.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline pancho

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Reply #2 on: November 18, 2018, 06:51:03 AM
on double-checking connections, i cant seem to see any poor solder joints. Resistances are all OK. Both LEDs check out fine so I don't think I fryed one. Is it possible I got a weak tube?



Offline Paul Birkeland

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Reply #3 on: November 18, 2018, 07:04:14 AM
Can you recheck the voltages at terminals 1 through 5 and post them here again?

There are certain voltages that would indicate a bad 12AU7, but what you're reporting does not indicate that at all.
« Last Edit: November 18, 2018, 07:07:31 AM by Paul Birkeland »

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Paul Birkeland

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Reply #4 on: November 18, 2018, 07:09:53 AM
These also appear to be incorrect.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline pancho

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Reply #5 on: November 18, 2018, 07:53:18 AM
Found that B5 was hooked to B1, not B2. Fixing this, i now have proper voltages at each terminal. were you saying i needed to switch the wires coming from B1 and B2?



Offline Paul Birkeland

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Reply #6 on: November 18, 2018, 08:09:59 AM
Found that B5 was hooked to B1, not B2. Fixing this, i now have proper voltages at each terminal. were you saying i needed to switch the wires coming from B1 and B2?
I just noticed that the wires that went to T1 and T2 from the 8 pin socket weren't connected properly.  I didn't notice the miswire from B2 to B5.

I'm glad you got it up and running!

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man