[Hallicrafters] Some HT-37 questions

[wb8jkr at juno.com]

> Apparently they are known for power transformer failures.  Quote, 
> "It's not 
> a matter of IF they'll fail, just when they'll fail".

 That's true of the HT-32 as well.
 
> Taking this into consideration, I have some questions as I 
> deliberate the 
> upcoming task of overhaul (I'd hate to put a lot of work into it and 
> find 
> the transformer is already shot).
> 
> 1.  How can I determine if it's already failed?  Does it smell 
> "smoked" or 
> show other indications (I know some failures can be invisible).
> 
> 2.  Would it be safe to pull both rectifier tubes out and test it 
> that way 
> for failure, checking for tube filaments, Voltage on the plate 
> connections 
> of the rectifiers etc?

 Absolutely. The typical failure mode is the HV secondary
shorts to a filament winding, but that's not gospel.
 
> 3.  Assuming the transformer is good, are there any things that I 
> can do to 
> reduce/eliminate the chances of transformer failure.  Things like 
> putting a 
> lamp in the case for a week or two to "cook it", solid state 
> rectifiers, 
> fans, separate filament transformer to reduce load on the main 
> transformer 
> etc?

 Not really. eliminating some filament current isn't going to
help enough to bother with, and the stock rectifier tubes
will allow a "soft" start up.
 
> 4.  Are there any other "issues" with this rig?

 Don't do a RF alignment unless its absolutely needed,
because it can be a real pain. The alignment of the
SSB generator isn't too bad though, and should be checked.
 
> 5.  FINALLY, if the transformer IS already bad, and having a slim 
> wallet, 
> would it be realistic to pursue fixing the transmitter up, or would 
> I be 
> much better off "parting it out (It's really quite nice overall)?

 A Peter Dahl replacement transformer is about $250.00
and you can get the original unit rewound for about $190.00

 Or you could buy a "parts" unit with a good transformer for
$50-$100 and hope for the best.
 The HT-37 when running right is a good transmitter and the
audio quality is outstanding!


73, Mark  WB8JKR

 
> 73 de Phil,  KO6BB
> http://users.mercednet.com/beaconeer/
> Merced, Central California, 37.3N  120.48W  CM97sh
>