[R-390] FL101 Rebuild (R390)

[Barry]

It occurred to me to simply test them!  They're running from about 70nF to 80nF and the inductors check between 1.0mH and 1.1mH

I suspect the capacitors may have been 0.1uF.  Does that sound reasonable?

Thanks,
Barry - N4BUQ

----- Original Message -----
> From: "n4buq" <n4buq at knology.net>
> To: "R-390 Mailing List" <r-390 at mailman.qth.net>
> Sent: Saturday, October 22, 2022 11:38:32 AM
> Subject: [R-390] FL101 Rebuild (R390)

> After finding the connection between the input and output for the "A" connection
> was open in FL101 of my R390, I removed the filter, opened the lid (lots of fun
> there...), and found the problem.
> 
> Along with the ubiquitous wooden blocks and wax, I found that the connections
> for virtually all the capacitors were bad or going bad.  The caps in mine
> filter have three connections where the end points are the through connection
> and there's a center connection that serves as the third connection allowing
> the capacitor's ground connection.  Each capacitor was housed in its own cute
> little thick paper box - a rather unique configuration that I'd not seen
> anywhere else.
> 
> I'm not sure what caused it, but the endpoint connections were such that I could
> simply pull the wires away from the capacitor and the capacitor for the "A"
> connection was the worse of any of them.  I don't know if those are
> electrolytic and the electrolyte leaked (doubtful as they aren't really sealed)
> but something caused quite a bit of dark corrosion which had virtually
> destroyed the solder connections.
> 
> In any case, the inductors are still in great shape and I can rebuild it so a
> relatively happy ending for this once I get the necessary parts.  Anyone know
> the proper value to use for those caps?  The filter is stamped with FILTER TYPE
> 97JX56 and I wonder if those numbers indicate the inductance and capacitance
> value (e.g. possibly 56pF but that's just a guess).
> 
> Thanks,
> Barry - N4BUQ
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