Short circuit in Peavey Valve King VK212
Remove power tubes one by one until the short goes away. Replace the one that causes the short to go away.  Repeat after replacing the dead tube as there could be more than one bad tube.
Alternatively, pull all the tubes out and measure the filament resistance. Look for values that are out of the ordinary - for a 12V tube, the resistance should be around 40 to 50 ohms.  Any value extremely higher (or open) is bad, any that looks like a short circuit is bad.
The point you are looking at connects to a flag marked &quot;HTR&quot; via R213.  &quot;HTR&quot; is probably the heater supply for the tubes.  If a tube goes bad, then the heater filament could short to ground and cause your problems.