38 116 RF tube - Printable Version

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38 116 RF tube - SteveJB - 11-17-2016

I gave a 38 116 to my cousin. I have replaced all caps and out of tolerance resistors.  It played well over a year.

Recently it died so I drove out to see him over the weekend. 

Cheking tubes, the RF rube was dead. I also had no voltage on the plates of the first audio and oscillator (6N7 and 6A8). All components there were correct and not shorted or open where appropriate.   While we wait for a new tube, would a dead RF tube cause the radio to go silent?  I think so but would like an expert opinion to help with troubleshooting if that's not it.

Thanks 
Steve

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RE: 38 116 RF tube - Mondial - 11-17-2016

You might check the resistor numbered 117 on the schematic. This is a chassis mounted wirewound resistor that drops plate voltage to the oscillator and AF tubes. If it opens you will lose plate voltage to the affected tubes.

Also filter cap 70A could be shorted, causing resistor 117 to open.

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RE: 38 116 RF tube - SteveJB - 11-17-2016

Thanks. I was thinking that.  I'll check that resistor next trip out there. I need to bring an iron and some tools with me then.

The filter caps are good. All the voltages were close and all they are all new.

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