[Drake] ceramic trimmer capacitors

[wa4tuk]

I would avoid cleaner. I might try to disassemble and clean. I had 
similar problems in a NCX-3. The cleaner caused the rubbery looking 
insulator sandwiched within the cap to swell leaving an unusable 
trimmer. My solution was to mount a even older APC style air variable 
under the chassis. I only needed to replace one trimmer and this NCX-3 
was previously neglected/abused so I just wanted it to work electrically 
correct.

Mouser has the really tiny style trimmers to 250 vdc in stock. I'd study 
the circuit to see if that's good enough. It would give you a fall back 
position if disassembly and cleaning when badly.

Pat
wa4tuk


Darryl Trump wrote:
> I think I am having trouble with the crystal trimmer capacitor for the 
> LO crystal oscillators in two of my three Drake rigs.  I'm talking about 
> the little white ceramic button about 5/8" in diameter that sticks up 
> through the chassis and is adjustable.  I think mine may be making 
> intermitant connection, drifting, microphonic, and otherwise problematic.
> 
> Question:  Is this a common problem with sets of this age that use this 
> type of capacitor?
> 
> Is there a fix other than replacement?  Can you clean and/or lubricate 
> these things, and if so, does anybody have a favorite technique?  I have 
> cleaned and lubricated many a wafer switch or potentiometer, but never 
> tangled with these trimmers before.
> 
> Thanks,
> 
> KB8BKU, Darryl
>