06-02-2014, 08:01 PM
I'm in the process of restoring a philco 71H, recapped it and changed out all resistors that were out of tolerance. after initial power up i notice considerable hum from frequency ranges 850 down to very bottom of dial, after testing the tubes i have 2 - 39/44 ... both test very good.....however 1 of these tubes glow at the top (made by raytheon) and the other (RCA) does not? i have a stark tester and checked for shorts on both tubes and there was not any. does anyone know if all 39/44 tubes should glow? just wondering if maybe my stark tester is not picking up a maybe dud tube here.....??