Oh NO! Left channel down! [resolved]

Ivan303 · 55297

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Online Paul Birkeland

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Reply #15 on: June 06, 2023, 03:09:29 PM
5670 in.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ivan303

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Reply #16 on: June 06, 2023, 03:16:40 PM
Tube in:

x pad .777V

Pictures attached.

As there are no broken wires that I can see and it's been running perfectly for nearly a year then just up and died,  a failed component on the board maybe?

Thanks



Online Paul Birkeland

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Reply #17 on: June 06, 2023, 03:22:14 PM
I would put a new 431 regulator on the B side and see what happens.  Also if you set your meter to beep for continuity, check each pair of legs on each transistor to be sure that none of them are shorted out.  It can be challenging (for me at least) to sort out whether the C4S is allowing the 5670 to draw too much current or if the 431 regulator has failed.  Based on your voltages, a shorted 431 regulator is very plausible, and they do fail from time to time.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man



Online Paul Birkeland

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Reply #19 on: June 06, 2023, 03:55:53 PM
I don't know who Sparkfun gets to make their parts, so maybe go with this instead:
https://www.mouser.com/ProductDetail/Texas-Instruments/LM431ACZ-NOPB?qs=QbsRYf82W3GYwUIvsPyMPw%3D%3D

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Ivan303

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Reply #20 on: June 06, 2023, 04:50:18 PM
DONE!

Thanks!



Offline Ivan303

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Reply #21 on: June 10, 2023, 02:36:25 AM
All 4 LEDs now light and...

Back in the system and making music!

Thanks!