First with the 5U4 out there is no voltage to the filter caps. Do the
dim bulb again with it in.
If it is a series string pull any tube out & run that test. If a // string
pull the hoz output tube. If things look good put the tube back in &
see if you get a raster in < 1 mn. If not the trouble shooting starts !
IIRC this is a "doughnut" chassis. They are a bitch to work on so take it very slow ! The idea is get the power supply up then the HV for a raster.
At that point you can judge how far to go.
The filter caps will probably work but need changing eventually, For now dont
spend the $$.
73 Zeno
LFOD !