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FDP Forum / Fender Amps: 1985 - Current / Twin Reverb (after 2000) vibrato repair - pumping noise



Jan 15th, 2018 12:53 AM   Edit   Profile  

I'm trying to help a friend on a repair. When I was in his shop last time I met him working on a repair of a newer Twin Reverb and he was already working two days on it without success.

When pushing the vibrato footswitch a pumping noise occurs - in the frequency of the vibrato, yet no signal at the input. The noise starts loud and decays to still some noticeable value.

In the circuit diagram (could someone locate the schematics for me, please?) one could see that the output goes to an opto-isolator, but in the real amp an SMD board (can be seen on the photo) is fed with the signal.

Can anyone help please? I will supply more information if necessary.



P.S. I found a PDF in the net which seems to show the circuitry despite of the little opto-isolator board.

(This message was last edited by ChristophK at 09:33 AM, Jan 16th, 2018)



Jan 15th, 2018 09:40 AM   Edit   Profile  

My friend got it sorted out: dressing and bunching the wiring made the ticking noise go away.

FDP Forum / Fender Amps: 1985 - Current / Twin Reverb (after 2000) vibrato repair - pumping noise

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