Pot replacement....I got "shafted"

[acorkos]

I ordered a replacement 50K reverse audio bracketed 16mm PCB mount pot to replace a broken pot on a Fender '65 Twin Reverb Reissue...trem intensity...from Music Parts Guru. The original pot had a solid shaft. This replacement has a D-shaft....so the knob doesn't fit correctly. Anyone have a super-secret mod to get these solid-shaft knobs to fit a D-shaft pot?

[Mars Amp Repair]

BONDO! Just kidding.
I'm guessing that even if you misalign the knob & tighten the set screw that the knob still moves eccentrically?
If there is a position that you can tighten the set screw on the round part of the shaft & the knob doesn't move eccentrically, then perhaps you can rotate the pot inside the chassis to make the knob align properly on the faceplate.

I've also wrapped that metal duct tape around the shafts to slightly increase the radius of the shaft to make wrong size knobs fit the shafts. No other secrets, tho. glen

[Jazz P Bass]

Fender knob

Well. you can either buy the correct pot, keeping the amp factory, or buy the D shaft knob.
I would not know where to get one to match the other knobs.
The correct part# for the 50K pot is: 037598 CTRL, 50K, 10A Used in R9, R20
You could call Fender for the part.
Or :Guitar Parts & Amp Parts These guys are real helpful.
Here is a link to the service manual, includes the parts list.
http://buildthemusic.com/content/amp..._%20manual.pdf

[Regis]

Go to a good hardware store and get a piece of brass tubing that will fit snugly over the d-shaft. Cut a piece to fit, install the knob and tighten the setscrew.

[J M Fahey]

Very small piece of wood or plastic and 2 minutes with a box-cutter carving it to supplement the "empty" part of a D shaft compared to a cylinder one. Once the knob hole is full, the screw pressure will hold it tight.

[acorkos]

thanks for the tips!

at my day job (dentist), i've got a supply of self-curing acrylic (methyl methacrylate)....i mixed a small amount, added it to the slightly roughened "D" shaft...molded it a bit by eyeball. after it started to set, i slipped the knob over the shaft to make sure it wasn't overcontoured. after it set completely, i installed the knob, tightening the screw into the acrylic. so far, it's holding....and it feels pretty studly. i'll give it a good crank down tomorrow. hopefully, it's good for the long haul

[olddawg]

JB Weld....It's like bondo but has metal in it. You can even drill and tap the stuff.

[Enzo]

A dentist.

Gee, kinda puts "Crown amps" in a new light.

Remember to floss between the controls.

[Mars Amp Repair]

Interesting and I was just joking about the Bondo...g