Thread: RCA CTC4B "Gainsborough" picked up in San Francisco
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  #65  
Old 01-20-2016, 10:59 PM
old_coot88 old_coot88 is offline
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Another trick using the variac is to put your AC voltmeter on the heater supply (preferably right where it comes out of the xfmr), and set the variac for exactly 6.3 VAC, then see what primary voltage is.
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