In message
,
Jethro writes
On Mar 14, 7:23*pm, Ian Jackson
wrote:
In message , John
Rumm writes

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)

Quite. WD40 is the sort of thing that any self-respecting d-i-yer
usually has about his/her person. Some pundits roundly condemn it as a
switch and pot cleaner/lubricant, but I find it usually works just fine.
--
Ian

WD40 is an oil, of some description. It's great for repelling water,
and soaking into threads. But it really has no place in electrics.

When I worked in the motor trade, I would despair of people - egged on
by the AA - who thought a spray of WD40 was actually a full service.
In reality, the *proper* job was to keep the HT leads clean, to
prevent moisture settling. Once WD40 had been used, you'd get a layer
of grime, which actively trapped moisture, and made it impossible to
start the car.

I would never use WD40 on things like cables (especially HT leads)
unless I could wipe most of it off afterwards. But pot and switch
cleaner/lubricant is a different matter. My tiny Electrolube dispenser
got used up about 40 years ago, and I've been using mainly WD40 ever
since.
--
Ian