[R-390] Looking for a 5-25 pF Trimmer

[Barry]

Hi Bob,

Well, I needed someone to tell me that before last night!  :-/

I thought those caps were a bit less fragile than that but I know better now.  I really should have known better in the first place but I got caught up in the swing of having the signal generator out and hooked up to the radio and seeing improved results in the performance as I went through the alignment.  20/20 hindsight...

Thanks,
Barry - N4BUQ

> Hi
> 
> Ceramic trimmers “freeze up” in a whole lot of older gear. The problem is in
> no way unique to these radios. Any time you see one that is “many decades”
> old, be careful with it !!!!
> 
> The “if I just apply more force it will turn” approach is generally NOT a good
> idea with these beasts.
> 
> Bob
> 
>> On Sep 20, 2024, at 3:34 PM, Jacques Fortin <jacques.f at videotron.ca> wrote:
>> 
>> Hi Barry,
>> 
>> "Frozen" Erie trimmers are a common problem in Collins radios (S-line and
>> etc.).
>> Glen Zook wrote a procedure to "repair" those.
>> But it does not always work.
>> When you got a frozen trimmer into the R-390A crystal deck, you have to
>> rebuilt the unit entirely (guess how I know).
>> 
>> About yours now: how much do you need ?
>> BTW, remove the rubber insulator: it is only there to prevent the rotation
>> of the thin ceramic disk, but what happen most of the time is that the small
>> disk "adheres" to the top portion and rotate with...
>> I will send you all the replacement parts if you still need those.
>> 
>> 73, Jacques, VE2JFE in Montreal
>> <Ceramic_Trimmer_Repair.pdf>______________________________________________________________
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