Originally Posted by
Al_The_Man
A big IF you can find a replacement H.O.T., the board has to be removed and a dozen or so printed circuit pins have to be de-soldered.
If it is just insulation cracked, I would try a clean with a non-residue electronic cleaner and attempt a repair by filling with an epoxy.
Cracking is usually a sign of overheating, but if it is still working OK, it may be just age.
Al.
Hey!!
Don't use epoxy. It is hygroscopic. You really don't want a water sponge as an insulator.
A silicon PCB conformal coating is much safer, or hard wax you can melt with a soldering iron. Put the PCB in a (conventional) oven at 100°F, 40°C for 4-6 hours or leave it cook in the sun before coating if you must fix it. You need to drive away any moisture. Do you have a vacuum chamber?
The retest to see that it not arcing, before coating.
Be aware there may already be carbon tracking on the surface and that must be repaired first.
Look to see where the arcing is. Don't fix what is not broke.
And after discharging the tube, wipe all of the tube around the HV (ultor) connection with isopropal alcohol.
Don't use methylated spirits. It leaves some sugary stuff behind.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.