[Hallicrafters] Some HT-37 questions

[Edward B Richards]

Hi Phil;

I concur with what has already been said. I also recommend lowering the
line voltage to what it was when the transmitter was designed; 115-117
VAC. It is now 122 VAC. See BAMA site http://bama.sbc.edu/ about 1/2 way
down the home page to an article on Voltage Reducers by K6UUZ. You could
connect the unused 5 volt winding in series with the primary out of phase
and obtain a 5 volt reduction in line voltage. Good luck.

73, Ed Richards K6UUZ


On Sat, 13 Nov 2004 22:03:17 -0000 "Philip Atchley"
<beaconeer at mercednet.com> writes:
> Hi Y'all,
> 
> I have acquired a Hallicrafters HT-37 HF transmitter that is very 
> nice 
> physically, electrical status unknown.  This will probably be a 
> "overhaul 
> project" later this winter (when I finish the SX-101A and the 
> BC-1004 
> presently on the bench, they both belong to friends). But I've 
> received some 
> Emails about the HT-37 that have me a little concerned.
> 
> Apparently they are known for power transformer failures.  Quote, 
> "It's not 
> a matter of IF they'll fail, just when they'll fail".
> 
> 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?
> 
> 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?
> 
> 4.  Are there any other "issues" with this rig?
> 
> 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)?
> 
> 73 de Phil,  KO6BB
> http://users.mercednet.com/beaconeer/
> Merced, Central California, 37.3N  120.48W  CM97sh
> 
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