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 Post subject: Heathkit Tube Tester Calibration
PostPosted: Jul Thu 15, 2021 1:39 pm 
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Joined: Jan Fri 27, 2017 8:41 pm
Posts: 367
Location: Springwater, NY
This is a collection of links containing posts by knowledgeable persons regarding the "calibration" of the common emissions testers. In my case, a Heathkit TC-2. Following the links, there is a summary.

https://antiqueradios.com/forums/viewto ... 8&t=292033

viewtopic.php?f=8&t=378977&hilit=3413

viewtopic.php?f=8&t=140484&p=3123944&hilit=3413#p3123944

viewtopic.php?t=72031

https://antiqueradios.com/forums/viewto ... 8&t=309952

These are not lab-grade instruments. At the risk of oversimplifying, all else being equal, these links teach us to adjust the 1200 ohm meter circuit resistor so that the 30VAC winding measures 30VAC when the line adjust meter indicator is centered. When this is done, the filament voltages will all come into proper range and the tester will be "calibrated" in the common sense.

Before doing this, my TC-2 heater voltages were low by >10%, worse under load. In my case, with the original rectifier, "75K" resistor, and meter, the 1200 ohm resistor was replaced by 750 ohms to get 30VAC.

Edit to add Fred J. Lingel, "A serviceman's tube tester," p. 57, Radio News, October 1947.


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Lingel A Servicemans Tube Tester.pdf [897.16 KiB]
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