[R-390] Cleaning the Megacycle bandswitch

Larry H larry41gm at gmail.com
Wed Oct 10 20:02:12 EDT 2018


I believe that most of the RF deck switches are ceramic, so a little
cleaner or solvent on them is not a problem.  But, the 2nd xtal osc switch
is phenolic and it can absorb chemicals and damage it by reducing it's
insulating characteristic.  Care to not get any cleaners or solvents on
them is important.  Deoxit is good to use on them, but not on  the phenolic
part.

Regards, Larry

On Wed, Oct 10, 2018 at 7:32 AM Guido Santacana <gsantacanav at gmail.com>
wrote:

> What I have done to clean the switch in the rf/crystal deck is to go over
> it carefully with a camel hair brush dipped in Deoxit. This is done just
> before returning the RF deck to the main chassis. When everything is back
> in its place I move the switch through all bands. It has worked for me.
>
> 73s
>
> Guido KP4FAR
>
> Sent from my iPhone
>
> > On Oct 10, 2018, at 9:37 AM, dog <agfa at hughes.net> wrote:
> >
> > It appears that the gain in my 390A will change over time. I've tried
> changing tubes to no avail. Then I noticed that if I rocked the Megacycle
> Change the gain goes back to 'normal' and stays there for a while. It's
> also noisy changing bands. What is the recommended procedure to clean that
> switch?
> >
> > Dave
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