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Fender Deluxe AB763... vibrato not working

Started by Hawk, May 10, 2018, 11:06:53 AM

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Hawk

Vibrato not working..can hear a very feint ticking sound. Suggestions?

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Hawk

According to the layout the voltages are correct on the "diode" side of the opto...there appears to be a resistive element in the opto, anyone know what value that should be?...

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Jazz P Bass

The resistive element should read around 1 Meg ohm when dark.

The reading should drop (not too sure how far) when light shines on it.

Hawk

Can't see a light. Should it be fairly obvious?

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Hawk

Definitely not seeing a light. Tried adjusting the intensity and nothing. Measured 68k not 1 meg...the plate end of the 10meg resistor  measures 190v whereas the layout shows 380v...the 10 meg is good and the voltage on the other side of the 10 meg is good...does a faulty opto effect the plate voltage?....I checked the resistance on the lightbulb side and found 13 Megohms...

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Enzo

It is a neon lamp in there, so no continuity expected.

Hawk

Thanks Enzo. I've ordered a new one. Hopefully it's the problem... haven't had any experience repairing these so first time for everything

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Hawk

Opto installed. All is well!

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