Zenith Roundie Changes, Improvements, & Issues

[Electronic M]

The 2 letters in the chassis number were model year M and the color TV chassis designator C. The first digits are tube count and the last were feature level. I've had both a 25MC33 plain Jane console and a 25MC43 remote set and the main difference was addition of the socket and wiring for the remote reciever chassis and the motors on the tuner and tint pot.

Zenith had 5 chassis years of color roundys the J, K, L, M and N year chassis.

The 24MC chassis you have has 1 less tube it could be a cost saving measure or a case of engineering trying a SS part and needing 1 less tube. It should be the same year as the other set you have.

The linearity coil forms can be brittle and or melted treat them with care...Zenith's don't eat flybacks like RCAs so I typically don't tweak output current unless it's fairly out to lunch. Even into the rectangular era Zenith's have been noted to have vertical transformer failures.... I've been lucky enough to not experience it yet (knock on wood) having at least 9 different tube color Zenith's come through my hands.