[Hallicrafters] Re: HT-33B HV problem

[Grant, Ken]

Hi again,

 I guess that I should have mentioned that the choke used, L3, is a swinging
choke. It's claim to fame is that, in a properly designed choke input
filter, it provides good voltage regulation at both high and low load
currents. The Peter Dahl replacement is spec'd at 55Hy at 50 mA load and 8Hy
at 400 mA load. Any ARRL Handbook from the vacuum-tube era will describe a
swinging-choke's operation.

 The 2700V line in the HT-33B supplies current to a 450V regulator. This
regulator draws about 55 mA at idle. I guess that it also does double-duty
as bleeder.

 The load current for 1KW input would be about 400mA.

 With the discovery that the choke's insulation has broken down, we've
pretty well decided that the plate transformer is okay. It was just a
red-herring.

More to follow. Thanks for the suggestions.

Ken, VE3FIT



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