Testing rectifier tubes - Printable Version

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Testing rectifier tubes - BDM - 08-22-2008

Gents, can a rectifier tube, such as a 35Z5 be checked properly using a DVOM?

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- Guest - 08-22-2008

Brian - You can check for continuity in the heater circuit. Because of the tap on a 35Z5 for a pilot light this means there should be a small resistance between pins 2 & 7, also between pins 2 & 3, and between pins 3 & 7. The most important measurement is between pins 2 & 7 - if that is open, the tube is shot.

The meter should indicate an open circuit from pin 8 to all other pins, and from pin 5 to all other pins.

If the heater circuit is continuous, there is a good chance that the tube will work, at least a little.

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- BDM - 08-23-2008

Thanks Robert. Must be good. Pins 2 & 7 have about 30/35 ohms. Same with pins 3 & 7.

Brian

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- Texasrocker - 08-23-2008

one thing about questionable rectifier tubes, if there is a internal- short in the plates, they can produce a nice mini-light-show for free!

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- Michael Dennis - 08-27-2008

Texasrocker Wrote:one thing about questionable rectifier tubes, if there is a internal- short in the plates, they can produce a nice mini-light-show for free!

Yes, I recall such a lightshow inside a 6X5 some years back.

Best regards. Mike

"Did you say 'utes'?"

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