Zenith 23XC38Z Chassis Losing Horiz. Width

[fsjonsey]

Hey everyone,
My daily watcher 1967 Zenith with the 23XC38Z chassis has been slowly losing Horizontal width at both edges of the screen over the past few weeks, however, the shrink has been much more noticeable over the past couple times I've had the set on. It gets about 2-4 hours of use a day, five days a week, and Ive been in using it in this capacity since about 2011. In that time, I've replaced a few bad electrolytic caps, the focus rectifier, a horizontal output tube, and a Damper tube. Does anyone who has any familiarity with these late 60's zenith Tube Chassis sets have any pointers on where to look for problems with Horizontal Width on the 23XC series chassis? Any help would be greatly appreciated.

I've been putting off pulling the chassis to install the NOS Channel Master Rebuilt 25GP22 I picked up a few months ago. It looks like this problem gives me a reason to get off my butt and finally do that.

Thanks in advance.