I probably have a weak damper, It's still the Original tube that came with the set, and I'm surprised it still works at all.
The HOT and HV rect have been replaced already.
I am seeing some changes in width and focus as i turn brightness up and down , so I will see what a new damper does.
there were 2 choices for HOTs in this set.
https://i.imgur.com/M0UzLQc.jpg
it came with an original GE 6JS6A which looked very tired, I have a 6HF5 in it now that someone claimed tested at %98.
which i have been running for 3-4 months now.
just on a lark, I put the old tube back in, it came on for 40 sec, shorted out, and blew the breaker, new tube back in and working, YUP, tube was worn out!