[sdiy] Shorting pots

[Colin Hinz]

On Tue, 28 Oct 2008, David G. Dixon wrote:

> [...] I have now come to the conclusion that (other than a noise transistor
> which isn't very noisy) all of the remaining problems with my circuit are
> due to shorting potentiometers (alas, a very cheap variety of Chinese 16-mm
> B100K's from my neighborhood electronic components store).  Specifically,
> contact seems to have been mostly lost between the connectors and the carbon
> strip, such that tugging on the wires (or even slightly jarring them in some
> cases) re-establishes the connection, with highly variable results with
> respect to the resistance/voltage obtained.
>
> This leads to my stupid question(s): How sensitive, in your experience, are
> pots to being soldered, desoldered, and resoldered?  Are some pots more
> "reusable" than others, or, having been used once, should they be tossed in
> the bin?  Also, must one be particularly careful when soldering pots,
> generally?

Good pots can be re-used lots and lots of times. They don't have
to be the 2W mil-spec jobs, either. Just anything that's made well
enough to actually work in service should handle reasonable soldering
and desoldering cycles.

Garbage pots are garbage from the moment they left the factory.

I haven't run into garbage pots yet, but considering where I get the
cheap ones, I probably will some day. I've certainly suffered my share
of garbage jacks and plugs, though. Whenever possible, I cable up a
project with a thought towards ease of panel component replacement --
optimally, making connections to the pcb through some form of connector.
Easy to do with one's own Veroboard creations, harder to do with some
of the pcb's out there, and a whole lot harder when it comes to the
rat's-nest fetishists (who shall remain nameless).

- Colin