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In Reply to: RE: Quick one: Does anyone have Hickok 539C test data for 307A (VT-225) tube? posted by PeterI on March 20, 2014 at 12:19:35
My 539 book does not include tube information for 307A but perhaps
the information for using a 600A on this tube will help.
Press button P4
Mut Cond 2500
Please let us know if this works?
Regards to all,
Thanks for info, unfortunately no result. The filaments didn't light, so it's those 1st two letters that have to connect the filament pins.
I can't find another corresponding tube with same pinout.
Roll Chart for the KS-15559 and KS-15560 testers shows the following:
5.0 JR-3020-4 7.0 Hi-3 P4 2000 @36% CAP=P G1 as control grid
@ = cathode activity limit
5.0 JR-4020-3 7.0 Hi-3 P4 900 CAP=P G3 as control grid, observe for min. Gm
I do not have a 539 (only a 752A in Hickok), so not sure what all the notations mean.
If, however, the filaments still do not light, then check to make sure there is actually continuity (I believe between pins 1 and 5).
The filaments have continuity but we just don't have the correct settings.
307A isn't even listed in Hickok's special WE data.
below is link to picture and pinout.
Realizing this will take a few minutes, I would put my voltmeter
test leads in socket pins 1 and 5. Set the meter for the range
that includes 5VAC and make a systematic search of the first two
knobs (filament). Seems to me you will have found the correct
setting when you see 5VAC on the meter????
Hope this works,
I checked my 600a and 6000 with a voltmeter. JR is definitely
the correct setting. I get about 5.9 volts no load.
I've a list of Western Electric tubes and JR is the correct
setting for virtually every tube.
Not sure what to tell you as I don't have a 539. Perhaps you can
figure out a way to measure the voltage with tube inserted??
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