Author Topic: No AC volage from TP1 on

May 28, 2023, 11:40:57 AM
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habasud

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Hi,

my MU524 fails from setup guide #6:

- DC voltages are present:
+/-16V, 48V B+, 33V @TP1+2

- Heaters are on 6.2V

- AC 1V/1kHz is at the in-/output when in bypass

- At "In"-pos. no AC voltage at all regarding TPs and output

I measure a short to ground from both grids and also across C4/R5 I think, this should measure at least some kOhms. Soldering seams clean.

Any ideas? Regards
Claus

May 28, 2023, 09:18:15 PM
Reply #1

habasud

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...think, I found out: Input transformer needs to be turned :-[

I'll be back soon.

May 29, 2023, 12:35:27 PM
Reply #2

habasud

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...after turning the input transformer in the right position, everything works as expected. Carefully reading the instuctions is helpful :)