Higher Capacitor Value For Safety Capacitor
If you come across HOT that always burnt after replacement then you should check out the capacitance value of the safety capacitor which is located nearby the flyback and the HOT. If you do not know which one then try to trace from the collector pin (center pin) of HOT and you should see that a non polar cap that have a high working voltage (from 1600v to 2000v).
Assuming you found that this capacitor value had out or no capacitance at all when test with a digital capacitance meter then i suggest that youfind the exact replacement. Now the problem is the capacitor value is not commonly found found from local electronic supplier. Since this capacitor value is critical you need an exact replacement of it. A too high or too low the capacitance value will have effect on the picture.
After done some research many years ago i found that any CRT Monitor that have this cap problem can actually take in a higher capacitance value with same or higher working voltage. Lets say you found the value of the cap was 5.1nf 1600v you can actually put in a 5.6 nf 1600 v or 2000v (2kv). The slighlty higher value will cause the display to become slightly bigger horizontally but acceptable because you can reduce the width from the front panel control button. If you put a too low capacitance value the Monitor will go into shutdown mode and may also kill the HOT. That means better to replace a slighlty higher value than to replace a lower value.
So, whenever you come across a shorted HOT please check this capacitor value and corresponding components before you install a new HOT and turn the Monitor On again.