On going Zenith 25MC33 roundy restoration

[compucat]

Originally Posted by Electronic M

I'll try to find time in the afternoon to look at the vertical circuit.

I tried the upper yoke string today and it seemed to affect the vertical centering, but the only effect it seemed to have was to allow me to either get it close to centered or WAY too high.
The way the static static magnets for all functions on the CRT behave makes me feel like someone screwed the magnets up on purpose.

Mr Squirrel, reminded me that my set had the wrong HOT as found. It had a 6LB6 where a 6BS6 IIRC was supposed to be used.

I have no clue what the exact original HV configuration was, but the wire on the HV filament is a different color than the stubs on the focus socket so I doubt the focus wire was reused on the HV tube.

If I get a schematic for it I might revert the focus circuit, but aside from my CTC-4 project set my other roundys are SS focus and do fine that way. I will at least try to tweak the focus circuit to give me more range as I have it set to min on the pot to get best focus, and would prefer to find a peak somewhere in the range.

My 25MC33 has the correct focus circuitry and even after replacing the focus rectifier tube and the resistor string it still requires the pot to be at one end of the range for correct focus. That might just be the way these sets are. I have seen many old sets that require the focus control to be at one end of the range or the other to focus correctly.