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August 09, 2022, 10:39:12 AM

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Fender 112 Deluxe Plus

Started by FenderDeluxe112Plus, April 12, 2022, 04:39:01 PM

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Just ran the preamp out into another amp. The buzz is there but it is quieter now and does not sound like the previous 100hz hum.
With the main filter caps replaced, could the next suspects be diodes breaking down under load in the power supply?


Yes, maybe check them.


I am reading 30.00vac at r82. Does this   suggest the rectifiers are faulty? You cannot view this attachment.



Look at your schematic.  R82 connects directly to CP5, which the schematic says has 31.9va on it.  Close enough.


Thanks Enzo,

Where would be the next logical points to test?


I get the impression you are not clear on diode testing, If so then
You check diodes with power OFF and lift one end of the diode.
Meter set to diode test.

If you get a reading both ways it's dud.
To save writing it all,, go here;



Thanks Phil,

This is the method I have been using so far, I thought there might be other ways to test in circuit.