Hallicrafters S-20R MW RF transformer

Greg Putrich gregp at N0QDS.ORG
Tue Aug 29 01:02:42 EDT 2006


Was troublehooting my S-20R tonight and found that the MW transformer in
the RF section (T13) is bad. There's no continuity between B+ & the
plate of V1. That's a slight problem as V1 is the RF Amp. Also looked
at it very carefully and I can see some thin grooves in the wax, which 
appears to be where wires once used to be (or I'm just seeing things,
but my meter doesn't lie to me). I checked the little resistor between
the plate and T13 and it's fine. Little question as that the transformer
is the problem.

Does anyone happen to have a transformer? It's a S.W. Inductor 51B231
(labelled as 51H231 in the radio). According to the manual:
"Transformer, 550-1780 kilocycle range, air core, special"

The other three bands seem to work alright. Much louder than the MW
band (hardly a surprise, since they get the RF amplifier). However,
need to revisit the radio yet again to fix the BFO circuit. And,
also to find out why three of the large resistors get rather hot (one
is a 5W that replaced the 2W original). Will do an alignment once
I get these problems (and any new ones) sorted out.

Also have a SX-28 that could use (at a minimum) new caps. Is there
any "easy" way to replace them? I've been putting it off for years
as some of those caps look like a major amount of work, if not
impossible to replace. 


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