[sdiy] Stuck mixer pots and reverb - two queries and an observation

[David Anderson]

> My mixer (1980s vintage) works OK and apart from some noisy pots, 
> which I know how to deal with more-or-less, works OK. However, some of 
> the rotary pots are as stiff as can be and some will hardly turn at 
> all; they seem frozen in place!
I'll bet you have a Tapco mixer. The put a grease in pots to make them 
feel "smooth". The only downside is what you're experiencing: the grease 
seizes. Here's a thread on a Tapco enthusiast site that might help. I 
used to have a Tapco that I thought I might replace the pots on but I 
never got around to it.

http://www.eskimo.com/~bgudgel/cgi-bin/messages/20.html

Checking quickly, the Tapco expert says you want dibutyl phthalate:

"Alright, Here's the secret to loosening up
tapco pots... Get some Dibutyl phthalate
and squirt a drop or 2 at a time down the
shaft at the top of the bushing and turn
back and forth. It shouldn't take very
much to free the pots up. The po ts get stiff
especially when they're cold as you've probably
found out already. You don't want to use too
much because then the pots can get and stay
too loose. Also, try to avoid using tuner/
contact cleaner if you can because it can
make the pot goo (the stuff that is sticking)
get onto the resistive element and make the
pot scratchy (electrically).
I'm not sure of a good source of Dibutyl
phthalate, but if I find one, I'll post it.
A good chemical outlet should have some.
Let us know if you find a good source.
It's a clear liquid and I know there are
references to it on the internet.
The pots themselves were made by CTS.
They were kind of special for tapco.
Bob"