I am trying to resurrect a long-neglected M28 printer that just doesn't quite want to go into LTRS. It looks like the LTRS function slide is pulling back OK, but the fork isn't moving quite far enough to the right for the LTRS-FIGS shift code bar to click into place.

If I nudge the fork just a little, the shift code bar will click to the right. If I pull the LTRS function slide back a little farther, the shift code bar will click to the right,

As best as I can tell, the LTRS-FIGS shift slide and the two breaker slide bails are behaving, the fork just can't quite get them far enough to the right.

I have tried adjusting the guide plate but with no luck.If I send repeated LTRS I can see the fork trying to move the shift code bar pin but never quite enough.

I feel like I am missing something here - actually I don't understand the mechanism that makes the LTRS-FIGS shift code bar click into place left or right (but I see that it does on a working typing unit so I guess that is normal behavior).

Is it possible that my LTRS function slide has just worn down and it can't move the fork enough?

Of course this is one of those stunt boxes with a zillion switches and a cable as thick as your wrist so I am really trying to avoid pulling it out to disassemble the shift fork mechanism.

Any advice greatly appreciated.