[Tubesforme]

I am wondering if anyone has checked the ohms on a Philco Model 20 power transformer using a DMM? I am interested in the reading between the CT, pin 6 of the power transformer to pins 1 and 2 (2.5VAC). Reading without any tubes or the pilot lamp installed. I understand that you should read .1 to .2 ohms, on either side, however my DMM reads 0.F on the auto range and on the manual range 0F. meaning 0 ohms. From pin 1 to pin 2, I measure .3 ohm. It is as if the CT is missing. I have checked and re soldered the terminals of the transformer and nothing changed.

I am checking this because of a 60 HZ hum that can only be eliminated by grounding the grid of the 27 audio tube. ALL COMPONENTS HAVE EITHER BEEN REPLACED OR SUBSTITUTED EXCEPT THE POWER TRANSFORMER. I am questioning the transformer because after turning it on and off a number of time, while testing, with or without tubes, I get a quick ARC sound out of the power transformer. I found out grounding the chassis to the house ground, blows the circuit breaker.

Hi,
> It is as if the CT is missing.
I'm not sure what the ct of the heater winding is doing. It's tied back to the bias buss (ct of HV winding) but the tubes that are connected on that 2.5v line are indirectly heated (will have no effect on the tube because the filament is isolated from cathode). My thinking is that it will work without that connection.

< I found out grounding the chassis to the house ground, blows the circuit breaker.
Really! Well if true and it's not tripping a GFI outlet I'd be looking for a power transformer(internal short)
If you need one I think I have a spare you can have for the shipping from Pa.

GL & Merry Christmas!
Terry

I misspoke. All of my outlets are on GFI's. That is the way all new buildings are built here in LA. It is the GFI that controls that outlet, that pops, not the circuit breaker itself.