1967 Zenith table set with 25NC37 Chassis

[BigDavesTV]

Nice looking and uncommon Zenith! Looking forward to "Simulated Television Reception" pictures! Remember when the pictured ads used to say that in fine print, below the picture of the TV for sale!

[Electronic M]

Originally Posted by drh4683

Ah, yes! Those were the big post-deflection purity rings! Zenith did it that way on the M and N line 23" sets. Very large and bulky apparatus and was secured with heavy copper braided cables that curved around the bell of the CRT. An unusual approach to purity adjustment. Not sure why Zenith did it that way in the beginning as I think the rest of the industry was using the much smaller and simpler purity ring assembly at the end of the tube.

Perhaps they did that (assuming it was adjusted electrically) to try to put the purity adjustments on the front....Zenith seemed to like to make as many of the service adjustments front-adjustable as possible.

[dieseljeep]

Originally Posted by drh4683

Ah, yes! Those were the big post-deflection purity rings! Zenith did it that way on the M and N line 23" sets. Very large and bulky apparatus and was secured with heavy copper braided cables that curved around the bell of the CRT. An unusual approach to purity adjustment. Not sure why Zenith did it that way in the beginning as I think the rest of the industry was using the much smaller and simpler purity ring assembly at the end of the tube.

I thought it was for purity adjustment.
I didn't know, that there was an "M" chassis 23V rectangular set, just the "N" models.
I know, that RCA had a CTC17E chassis, that was their first 23V set. It had the same control panel as the CTC16E roundie. Most of them, didn't have that great of a picture and had purity problems.

[dieseljeep]

Originally Posted by Electronic M

Perhaps they did that (assuming it was adjusted electrically) to try to put the purity adjustments on the front....Zenith seemed to like to make as many of the service adjustments front-adjustable as possible.

It was rear adjustable, with two large tabs, to move around.
If anyone remembers the Motorola ETS908 chassis, it had a dynamic blue lateral magnet, that was adjusted from the front, on the convergence board.
In the early days, they all had their quirks.