[R-390] R-390A FL-101 repair/replacement...

[Jordan Arndt]

I've received several responses so far, and I hope you guys keep them 
coming...!

For the time being, I''ve opened the old filter and pulled out the coils and 
caps and wired jumpers directly from input to output bypassing those lines 
with .01uF @ 2KV. At least that way, I can finish the work on that receiver 
before deciding on a final replacement method of FL-101 in that rig.

I found that each line has 2 toroidal inductors, one large at the input and 
one small to the output with caps across the large inductor to the case of 
the filter and the small inductor in series with the larger one, connected 
direct to the output connectors.

There is a lot more stuff in there than I had expected, and it's all double 
wrapped in a yellow film and then everything is potted in what appears to be 
beeswax(?).

73...Jordan VE6ZT


----- Original Message ----- 
From: "Jordan Arndt" <Outposter30 at shaw.ca>
To: "R-390 Forum" <r-390 at mailman.qth.net>
Sent: Monday, May 02, 2022 12:01 PM
Subject: [R-390] R-390A FL-101 repair/replacement...


>
> Hi group...
>
> I'm going to have to replace FL-101 in 2 receivers, and I'm considering 
> installing those Corcom computer type line filters in their place.
>
> One has a broken solder connector on the B side of the filter output, and 
> the one I was going to use to replace it shows both ~100uA leakage at 
> ~200VDC and <10Meg of insulation resistance in both the A and B lines 
> measured with my TO-6.
>
> I also tested the broken filter for comparison, and there is no DC leakage 
> at all, and the insulation resistance is as near to infinite as I can 
> measure on the TO-6.
>
> What is the recommended method to enlarge the opening in the rear panel to 
> the necessary dimension..?
>
> Would a Dremel tool with a cutoff wheel work..?
>
> Any tips are greatly appreciated....!
>
> 73...Jordan VE6ZT
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