Sticky Switch

[77640]

The p/u selector switch on my Series (77-640) I is real stiff. The pointer knob was cracked and I have ordered a replacement. It's 29 years old but Maybe the stickin switch had something to do with it cracking. I havent taken it out yet but can I lubricate it or is it sealed?

[David Houck]

My guess would be that, like the other pots, it is sealed.  And if, like the other pots, it is self cleaning, then you may want to try moving it back and forth through the positions twenty or thirty times to see if that frees it up.  But I'm just guessing, I can't recall this specific question being asked before; so a response from Mica or Val would be more authoritative.

[mica]

We've never seen one that needed lubrication, but if we did, here's what we would do. You can try using something very light like 3-in-1 oil or sewing machine oil to lubricate the switch. Put the bass on its back and use one or two drops where the shaft enters the bushing. Leave it in position for 5+ minutes to let the capilary action work (read: be patient). You don't want the oil to get down to the contacts, so really only use one or two drops.
 
The switch is military spec, with a very positive detent, so attempting to change positions without a knob is really hard.  
 
If you can try another Series I or II to compare and see if the switch is the normal stiffness.  
 
How long have you had the instrument? Has the stiffness/stickiness of the switch changed?