Masterpiece Band Switch Problem

[Dave]

Switch is worn and there's excess knob travel between band engagement. It will slip out of position especially "phono" during and between sessions of use. Anyone had success servicing this pot or is it time for a good used one or replacement ?

[Kent King]

Well, the band switch is not a pot, and not easily replaced. It is a multi-wafer, multi-position switch assembly. If it is not staying in position, I would look very closely at the detent mechanism. The detent is two small ball-bearings on spring metal that rotate into grooves to hold the switch in position. I suspect that on your set, one or both of the bearings is gone, or the plate they run in is very loose. There are several possibilities. As noted at the beginning, this won't be a trivial fix. On the plus side...if we can figure out why your detent is failing, I'm sure I've got enough parts chassis here to find whatever you need to fix it.

Kent

[Dave]

Good call Kent. Indeed one indent ball missing likely plates are compromised. Not sure how to proceed ?

[David C. Poland]

Can you determine if the metal that should hold the missing ball bearing is damaged?

FYI - it is possible to pull the band switch shaft. I partly pulled the shaft of the Scott Masterpiece on my workbench now, just to ease access to a few caps I replaced. If you are careful not to disturb the orientation of the several wafers, and mark the shaft for proper orientation, you may be able to pull the shaft entirely to remove the detent assembly for repair. Be really careful to note the locations of all the little washers and spacers if you attempt this. You want to avoid damage to any wafer or spoiling their alignment.

My junker chassis is already missing the band assembly, so detent assembly is already gone. Maybe Kent or someone else has that detent assembly  from a junker chassis.

[Kent King]

I'm sure I'll have the parts needed on one of my chassis. Probably going to be a real stinker to fix though. Can you send some pics of the inside of the chassis showing close up detail of the bandswitch line? That may help us...thanks!

[Dave]

Thanks for the replies Dave and Kent. I'll have to get back later when time allows. As it is, one of the indent balls is working, perhaps I should leave well enough alone.