From: liz@poppyrecords.invalid.invalid
Cursitor Doom wrote:
> On Sun, 15 Sep 2024 22:46:18 -0700, John Robertson wrote:
>
> > On 2024-09-15 9:44 a.m., Nick Hayward wrote:
> >> Hi all,
> >>
> >> I have a switch which isn't making electrical contact. It consists of
> >> two leaf springs. Dead simple. They're springy enough to push against
> >> each other alright. And I've cleaned them with ethanol (didn't work)
> >> isopropyl alcohol (didn't work) and Servisol switch cleaning lubricant
> >> (didn't work either). I am at a complete loss here. Has anyone come
> >> across something like this? I can confidently say I never have!
> >
> > Have you verified that the meter leads are making good electrical
> > contact to the switch blades? Oxidation can fool any of us! Touch one
> > probe to the switch blade, and touch the other probe further down the
> > blade - repeat on the other side, only then check for electrical contact
> > closure once you are certain you have good probe connections.
> >
> > John :-#)#
>
> Acting on the advice of someone very much more experienced with this
> attenuator than I am, it's the case that the offending material was
> silicon oxide. Something to do with contact sparking and silicon grease
> that they used in the early versions of this device. The only remedy is
> fine abrasive paper. I used 1500 grit in then end; very lightly just a few
> strokes. it's fine again now - and before anyone says anything, there was
> no gold plating on these contacts to rub off!
That's worth remembering. I had always assumed silicone grease was
fairly benign and could be used anywhere, now I know differently.
--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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