In message , Gary
writes
On 14/03/2011 18:28, John Rumm wrote:
On 14/03/2011 17:46, Jules Richardson wrote:

Picked up an old Kenwood tuner/amp for nowt a couple of days ago - I
love
all that old 70s/80s hi-fi stuff. All seems to be working, but has a
major case of the crackles when the volume control or input selector are
used. Despite all the putzing around with vintage kit I've done over the
years, this is the first thing I've had where it seems like the pots and
switches could do with a good clean.

So... does isopropanol work? I've used it on all sorts of other
electronics-related cleaning tasks over the years, but I've seen mixed
reports online about it for use with pots, with some folk saying it's OK
and others saying it'll destroy lubricant inside the mechanism (the
latter does seem like a valid concern, but I'm just not sure if it's
being over-cautious - or if whatever lubricant was used has long since
ceased doing a useful job in this thing anyway) .

What about ipa to clean, followed by a little mineral oil down the pot/
switch stem to work as a contact lubricant? Or is that asking for
trouble, too?

I'm trying to avoid the week's wait it'd need to get some conctact
cleaner shipped here - but if that's the way it has to be, then so be
it :-)

I have had this problem on a couple of amps. One I did using proper
contact cleaner, the other (also a Kenwood as it happens) I used WD40.
To be fair the WD40 did the better lasting job it seems!

(squirt into the pot from the back - same for the switch, then work
back and forth repeatedly for a bit)


I was in the repair industry for 30 years and the use of WD40 by the
public was great. It used to make a little problem into a big one and
give me lots of work..
Remember WD40 is an insulator. ( that's why it is used on car
ignitions) contact cleaner is not a insulator. it is a cleaner.

Basically an oil

and a good job it is an insulator, can you imagine the effect if it
wasn't and you sprayed a conductive film into e.g. a 1meg pot?




--
geoff