37-602 Cap question - Printable Version

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+--- Thread: 37-602 Cap question (/showthread.php?tid=18627)

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37-602 Cap question - Radioroslyn - 07-03-2018

http://www.nostalgiaair.org/Resources/207/M0013207.htm

Does #35 seem like a bad idea? To my way of thinking it would couple 60cy ac (hum) into the dc hv. Typically it would be from the plate of the 25Z6 to B-.

Tnx!

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RE: 37-602 Cap question - 462ron - 07-03-2018

I'm thinking #35 acts like a noise suppression cap that is placed across the line. It us a small enough value to be able to pass hash on the ac line but not much 60 hz component into the dc power supply!

Ron

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RE: 37-602 Cap question - Radioroslyn - 07-03-2018

The reason I mention it is that I had a set that was recapped by someone that miss wire a cap in this fashion. Should have been across the line not across the rectifier. It had a terrible hum. After checking the tubes for shorts and the filter caps I saw a cap across the 25Z5 socket wasn't shown on the diagram wired like that. Rewired it to B- and all was well.

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RE: 37-602 Cap question - 462ron - 07-03-2018

I know I've seen another set wired like this that I've worked on, can't remember brand or model. Maybe your cap is fairly leaky. No harm in rewiring it across the line with appropriate X safety cap.

Ron

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RE: 37-602 Cap question - Steve Davis - 07-03-2018

I see no good reason for that cap. I would try the radio with and without the capacitor.

Steve

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