116X plummeting B voltage - Printable Version
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116X plummeting B voltage - Guest - 02-17-2010
Hello,
Foolishly, I was attempting to align this radio with a screwdriver and shorted something in the process. I was very close to finishing and now, there is no sound, the wirewound resistor(part96), transformer (part 92), and one of the 6A3s all get very warm almost hot to touch. When I power up the radio, I observe the B voltage at the input filter(part103) climb to about 280vdc then there is a pop in the speaker and the voltage drops in a hurry to about 150vdc and things start to get warm.The power transformer seems to be ok. Live and learn, as I should have known better. Where should I look to troubleshoot this problem, please point me in the right direction. Thanks, in advance.
Marc
Re: 116X plummeting B voltage - Radioroslyn - 02-27-2010
Check for negative voltage on the grids of the 6A3's. Should be about -60v. If you don't have it on both grids Check the center tap of the driver transformer (92) If you got it there replace 92. Check for plate voltage on the # 42 tube. If is is low replace (92) Also try removing the #42 and watch the b+ to see if it drops as the set warms up.
Terry
Re: 116X plummeting B voltage - Guest - 03-01-2010
Thanks. I really appreciate this information. Through no effort on my part, the B voltage has resumed normal values...so the problem may actually an intermittent one. I will follow through. Marc.
Re: 116X plummeting B voltage - Radioroslyn - 03-01-2010
Glad to hear it seems to be OK. You may want to put a small fuse in the CT of the HV winding of the power transformer. Just to be safe. Should be a great sounding set! I've got the 37-116.
Terry
Re: 116X plummeting B voltage - Ron Ramirez - 03-02-2010
I edited the topic title to avoid confusion. There is no such thing as a 36-116X. The correct model number is 116X.
Intermittent problems can be the toughest ones to solve. Terry's given you some excellent advice, Marc; best of luck with your set.