Zenith 25EC58 Restoration Thread

[TinCanAlley]

Originally Posted by BeamT

Obviously bad connections, easily reflowed and cleaned up. Could very well be your problem. You will know soon enough.

I usually find the 125v B+ in the flat pan chassis such as your 25EC to be 120-130 depending on the line voltage. IIRC this supply is regulated by the resonant circuit formed by the power transfomer and the 3.3uf oil capacitor. There is no regulator that you can adjust. The 24v supply does have a regulator, set by the zener diode in the base circuit.

If your jail bars are vertical, as they typically are, the "ripple" is at a horiz rate leaking into the video, more likely the boost source.

Are you looking at Sams? Which one? or the Zenith CM?

I'm using Sams. Been unable to find the Zenith.

I'm attaching a couple pics of the main transformer and circuits as well as the horizontal and boost circuits. I'm getting better at using schematics, but get a bit lost seeing multiple voltages coming from the transformer to different points and combining and turning into completely different voltages. For instance, the voltage going to the Chroma module is 125V, but in the schematics, it is derived from two 100VAC lines, one 235VAC line. Don't get me started on the return of it going to a separate line derived from 26VAC line to a voltage regulator creating 23.5V.