C4S Board Voltage Fail

hughmann · 1772

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Offline Paul Birkeland

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Reply #15 on: January 09, 2024, 12:21:19 PM
I'd ohm out the pins on the tube itself to see if pin 2 and pin 3 are shorted internally or if pin 7 and pin 8 are internally shorted.

Paul "PB" Birkeland

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Offline hughmann

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Reply #16 on: January 11, 2024, 03:47:33 AM
I ohmed out the pins on the tube, pin 2 to 7 0 ohm, pin 3 to 8 OL, pin 2 to 3 OL, pin 7 to 8 OL.



Offline Paul Birkeland

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Reply #17 on: January 11, 2024, 05:38:58 AM
OK, reading back through this you were saying pins 3 and 8 are reading as shorted, but these are connected with one of the jumpers, so this is OK.

With the tube removed, are you seeing 0 ohms between ground and pin 3 or pin 8 still? 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline hughmann

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Reply #18 on: January 11, 2024, 11:14:24 AM
With tube removed both pin 3 and 8 read OL.



Offline Paul Birkeland

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Reply #19 on: January 11, 2024, 11:20:40 AM
Maybe double check that those go back to 0 when you put the tube back in the socket. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline hughmann

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Reply #20 on: January 11, 2024, 11:57:42 AM
Yes both go back to 0 ohm.



Offline Paul Birkeland

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Reply #21 on: January 11, 2024, 12:14:22 PM
You'd have to have a shorted tube for this to happen, and you should be able to measure that short by using your meter to check for continuity on the various combinations of pins 2, 7, 3, and 8 (pins 2 and 7 may read as shorted, which would be normal, but the rest should be open between all pairs).

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline hughmann

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Reply #22 on: January 15, 2024, 02:58:36 AM
Checked continuity on pins 2,7,3,8. All pin combinations read open except 2-7 which you said may read as shorted. Does this mean that something is wrong with the socket ?