[Drake] Need docs of Sherwood R-4C filter mod

[Jose V. Gavila]

Hello!

I have just got a nice R-4C with several Sherwood and other mods. Among 
them, it has a USB/LSB Sherwood filter pair but is not currently connected 
(coax is unconnected and taped at both input and output ends). I would like 
to find the info to connect them; how they are switched and so on. Thanks!


About the R-4C (S/N 18xxx), so far I have found it has the following mods:

-SSB/CW extra panel switch (ouch!) which selects an extra Sherwood 600Hz 
filter or the standard one, by menas of a 600-B dual TO-5 relay assembly.

-GUF-1 filter instead of standard Drake filter.

-USB/LSB Sherwood filters, with TO-5 relays

-Similar to Sherwood AMP-4 audio amplifier.

-Power supply filter (a couple of toroids in a PCB)


It has a problem, as the PTO bearing is damaged (most of the balls are 
missing), so I would need to locate an spare one. Anyone?

Thanks for your help!

JOSE
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      La Canyada - Valencia (SPAIN) - Loc: IM99SM

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