RE: I measured the DCR of good transformer

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Questions about tubes and gear that glows. FAQ

In Reply to: RE: Dynaco ST70 OPT failed secondary? posted by Tom Bavis on March 9, 2015 at 06:34:39:

and got the same readings above. The transformer in question measured a DCR of .2 ohms at the 8 ohm and 4 ohm tap. I'm getting a signal at each screen tap of the EL34's on the scope.
The EL34 gets extremely hot in a very short amount of time which tells me something is shorted and pulling excessive current. I haven't isolated the transformer out of the circuit to test but primary might be partially shorted as well since I see the cap charging(tubes out) across the plate windings. It doesn't do this on the good transformer.
The owner of the amp attempted triode wiring and had the screens crossed up between the tubes. Would this damage the transformer?

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Follow Ups Full Thread

Topic - Dynaco ST70 OPT failed secondary? - deafbykhorns 17:10:36 03/8/15 (5)

RE: Dynaco ST70 OPT failed secondary? - Tom Bavis 06:34:39 03/9/15 (4)

RE: I measured the DCR of good transformer - deafbykhorns 03/9/1513:13:29 03/9/15 (0)

Low Ohms Measurement - Triode_Kingdom 11:15:53 03/9/15 (2)

Thank you for the link - 1973shovel 04:55:33 03/10/15 (0)

RE: Ingenious, now I need to wrap my head around this - deafbykhorns 17:23:27 03/9/15 (0)

Follow Ups

RE: I measured the DCR of good transformer - deafbykhorns 03/9/1513:13:29 03/9/15 (0)

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