[R-390] Antenna Trim trouble/Capacitor Q question

Manfred Antar {KN6KBS} manfredantar at gmail.com
Fri Jun 21 18:42:45 EDT 2024


Get some Kroil - penetrating oil for the roll pin.
Let it soak overnight or longer then try again.
Works much better than liquid wrench.


> On Jun 21, 2024, at 14:39, Jordan Arndt <Outposter30 at shaw.ca> wrote:
> 
> I'm still unable to remove the roll pin, and the punch I was using actually broke off near the business end, so I'm stuck there for now.
> 
> Q:  What happens when you use 2 x 18pF SM caps in // to replace a single 36pF..?
> 
> Specifically, I want to replace C-211, a 36pF cap, but I only have 18pF and 39pF SM caps on hand.
> 
> Aside from ordering more caps, which is the "better" solution, using 2 x 18 or a 39pF cap to replace C-211...?
> 
> Your thoughts are much appreciated....73...Jordan VE6ZT
> 
> 
> 
> 
> 
> 
> ----- Original Message ----- From: "Jordan Arndt" <Outposter30 at shaw.ca>
> To: "'Collins R-390 HF Receiver List'" <r-390 at mailman.qth.net>
> Sent: Saturday, June 08, 2024 12:05 PM
> Subject: Re: [R-390] Antenna Trim trouble
> 
> 
>> 
>> Well, my first attempt to remove the roll pin was not a success...The pin didn't budge and the roll pin punch bent. I'll try the freeze/torch process and I hope that works. The punch I used was 1/16" which appeared to center and fit properly, but it was/is a fairly cheap tool. I may look for a tougher type of punch.
>> 
>> My problem did not appear to be grounding of the AGC line, only slight scratching as I turned the Ant Trim control, so using my Sprague TO-6, I tried to see if I could provoke "leakage" using the insulation resistance test of the TO-6, but to no avail...
>> 
>> That's all for now...
>> 
>> 73...Jordan VE6ZT
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