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

[Barry]

If I remember correctly, I opened one of those and merely used the connection points to wire a chassis-mounted filter.  That kept the line input looking original from the outside.

Several years ago, I had some adapter plates made that allowed a filter with a built-in IEC connector to fit on the back and used the same holes as the original filter.  That seemed to be the better approach and made for a nicer line cord socket arrangement (albeit some folks don't like having to keep IEC power cords around for such uses).

Thanks,
Barry - N4BUQ

----- Original Message -----
> From: "Jordan Arndt" <Outposter30 at shaw.ca>
> To: "R-390 Mailing List" <r-390 at mailman.qth.net>
> Sent: Tuesday, May 3, 2022 10:48:50 AM
> Subject: Re: [R-390] R-390A FL-101 repair/replacement...

> 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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