[Hallicrafters] HT-37 refurb/troubleshooting

[Greg Mijal]

If the black is carbon then something happened around those sockets that 
involved high voltage. Maybe a flash from a power supply situation. HV can 
also darken insulating surfaces over time.  Like O scope rectifier tube 
sockets. Suggest a load check and listen for funny noises too.
Whatever it is it doesn't need to be there. People that use the HT 37 on a 
regular basis nowdays recommend SSing the power supply with diode strings or 
plug- ins.

Greg
WA7LYO
in sunny Feenix

----- Original Message ----- 
From: "John D'Ausilio" <jdausilio at gmail.com>
To: <hallicrafters at mailman.qth.net>
Sent: Monday, January 29, 2007 7:54 PM
Subject: [Hallicrafters] HT-37 refurb/troubleshooting


> Good evening ..
>
> I've accquired an HT-37 to use with my Drake 2B, and it's in less than
> operable condition. It seems to work OK on 20 and 80, with some ripple
> in the tone. Nothing on 40,15,10 so there's evidently an issue with
> the heterodyne oscillator. Will be ordering caps to clean up the PS.
>
> I pulled it out of the case and took a look at the bottom and see lots
> of black around the bases of the two rectifier tubes. Doesn't look
> like anything's blown up in the area, and HV measures OK .. wondering
> what all the blackness might indicate.
>
> Any other hints/clues/part source info appreciated :)
>
> de w1rt/john
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