That looks like a bad HV reg pot. Width would come in a little.
Give it a little bump & it would snap in. Try cleaning the crap out of it & adjusting it. BTW on schematic it shows 2 versions of HV reg
circuit ( dotted lines ) see what I mean ? No 2 alike !
Tripler is made by GE & marked with Zenith part ##. Date code
is 72-48. = 48 th week of 1972. Set was born with it 99%.
73 Zeno
LFOD !