If the set is direct line powered, try checking the [likely to be
there] hybrid regulator module down stream from the 170 volt
supply.  Several sets I've looked at use a 135 volt regulator.  The
regulators have a tendency to short out, making the safety circuits
shut down the EHT supply section.

Try putting the set on a Variac or adjustable transformer and lower
the AC input voltage to the set to about 90 volts.  If the set
operates nromally, then you know you've got a shorted regulator.

There are myriad other areas for problems, but I've seen the one
above several times.  Also, if the set uses one, the trippler
module may be shot; that's fairly common.

