Tektronix 577 D1 Horizontal gain and drift instability

[Kjo]

This 577 is mostly working ok. All voltages are correct. I have cleaned most of the push buttons with DeOxIt but have not touched the covered cam switches. Tek manual says dont lubricate them.

The vertical operation is working correct with no instability. But the horizontal zero point (and entire characteristic curves set) drifts L & R and sometimes off screen. Occasionally the horizontal scale factor randomly changes. Can those cam switches wear out? I am looking for pointers as to where to start.
 
Update:
I determined that the horizontal instability was related to the NORM/INV switch. The TC has spent most of its life in NORM mode (who uses PNP stuff.) In INV mode there is no instability! This switch has 3 DPDT that only reverse 3 sets of connections. Nothing is switched in or out of the H & V amps. Unfortunately the switch is on the back side of the amp board. Im not going to try removing it, and there is no clear way to get contact cleaner to it.

I operated the switch 50-60 times and managed, for now, to clear what ever gunk was on the contacts in the NORM position. Interestingly, since the SW is locking IN for NORM, there are actually 2 parts of the NORM contacts that are used. The static position was gunked, but fully depressing the NORM switch and holding it uses a clean part of the contacts and the instability in horizontal went away.

I have been able to complete most of the basic adjustments fine. But this is a D1 with storage that is not working. I know it did work many years ago. It is not critical that it works and I am not sure I understand the circuitry involved. Something for the future...

Update:
The future is now...
I took some time to understand the flood gun storage schematic. I made a wild guess that complete lack of response might point to the cathode circuits. And sure enough, the heater bridge rectifier had some open diodes. Kluged up a bridge from 4 1N4002s and the storage system is up and running too.