12au7 not glowing [resolved]

watonwak · 130

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Offline watonwak

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on: May 23, 2024, 09:01:10 AM
hello,

i was doing some rework to my crack with speedball, tidying up joints to try and fix some intermittent noise, but now my 12au7 and its LED's no longer glow, and i am reading about 180v on 0A and 0B on the small board. Have i messed up something obvious? All other LED's light and so does the 6080. Thanks

Edit: I checked the LED's with my meters diode check and they do both glow
« Last Edit: May 23, 2024, 01:53:42 PM by Paul Birkeland »

Beyerdynamic DT 1990 Pros | Crack + Speedball + Alps Blue Velvet + Panasonic PP Output Caps


Offline Doc B.

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Reply #1 on: May 23, 2024, 09:44:46 AM
12AU7 heaters are not getting power. Check and maybe reflow the green wires connected at the A4/5 and A9 socket connections and also the other ends of those wires at B7 and B8.

Dan "Doc B." Schmalle
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Bottlehead Corp.


Offline watonwak

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Reply #2 on: May 23, 2024, 10:40:47 AM
Thanks Doc, it was the B7 end that had come off. It had snapped at the joint with not quite enough slack so had to replace the wire, but its all working great now!

Beyerdynamic DT 1990 Pros | Crack + Speedball + Alps Blue Velvet + Panasonic PP Output Caps