[Amps] Excessive Plate Voltage Henry 2KD-5

[Roland AH6RR]

Aloha All,
I have a Henry 2KD-5 that has been sitting for a few years and after doing some repairs and tube replacement  I turned it on and the plate voltage went to 4000V before I could turn it off. One of the filter caps smoked and now 1 has a short they all seemed hot, they are the orignal filter caps. I plan on replacing the all but I want to know if this will cure the problem. I checked the HV supply wiring and it is fine. Should I look at anything else?.
Roland AH6RR