DuMont RA-103 Doghouse Horizontal Problems

[M3-SRT8]

Originally Posted by Tom Albrecht

Well, something is not right here. If there actually were an open circuit from the points you mention to the B+ supply on the 5U4, the horizontal oscillator would not function, and you would have no picture. Somehow the measurement you are making doesn't seem correct. Not sure what to suggest other than to turn the set on and measure those pins for voltage, where I'm sure you will find that B+ is present.

I know. I'm getting a full raster.

I checked T3, the Horizontal Output Transformer, just for kicks. It read the following:

Pole 1 to 3: 407 Ohms, Spec 405
Pole 1 to 2: 168 Ohms, Spec 165
Pole 4 to 6: 7.3 Ohms
Pole 4 to 5: 7.1 Ohms
Pole 5 to 6: 0.5 ohms (this is the Width Adjustment)

So, that looks ok to me.

I'll do voltage checks, and get back to you...