[morzh]

First of, lowering the input AC Voltage does this: it brings the input within specifications.
While working about10V higher does not necessarily kill anything, it certainly makes tubes run hotter as the filament voltages increase proportionately, and increasing the voltage 10% raises 5he power 21%.
After that, if you have lower than needed voltages, you should figure out that one by troubleshooting, but one way of NOT fixing that is raising the input.