How to clean my tuning capacitor?

[Bill Bowden]

On Jun 15, 1:38 am, "Phil Allison" <phi...@tpg.com.au> wrote:

"Bill Bowden"


The cap got more erratic today, so I applied more WD40 and then lost
all signals except one 50KW station about 7 miles away. Everthing
appeared normal, oscillator and antenna circuit both on correct
frequency. It appeared the Q of the antenna circuit degraded
drastically due to WD40 which may have spilled on the capacitor
plates.


** More likely rust or dirt particles from the bearings made it between the
plates  -  carried by the  EXCESS  of  WD40 you applied.

I have used WD40 successfully on intermittent tuning gangs in FM receivers
many times, never any problem.

BUT  I used it sparingly and carefully  !!!

You may need to use an evaporative cleaner on the plates now  -  ie stuff
that smells nice and disappears in seconds if you spray it on your hand.

...  Phil

Yes, I think you are right. I disconnected the cap and connected an
ohmmeter across the plates and read many points of low resistance. So,
I soaked the cap in a cup of isopropy rubbing alcohol and rotated the
plates every few minutes and dried it out in the sun and then applied
a few drops of sewing machine oil and it seems ok now. I found
someone who has a ultrasonic cleaner to loan and will try it out next
week.

-Bill