[purman1]

I have a 40-190 that I re conditioned about two years ago. When I turned it on recently it started to play then made a horrific loud hum and I quickly turned off. Upon checking I found that there is in excess of 100 vac when measured between the plate windings and filament windings. This is not cool and was wondering if anyone else has experienced this problem.

[morzh]

First of, there will be large AC voltage as the filament is grounded and the plates are AC fed.
Second, check your rectifier on a tester, then your capacitors.

[purman1]

I am reading the voltages with transformer out of the circuit. This was after I checked everything I could think of that might be causing the problem. after Finding no other problems, I disconnected all of the secondary and filament leads including grounds and that's when I discovered the apparent short between plate secondary and filament winding.

[morzh]

If all 5 leads (filament and the HV secondary) are disconnected and you still read the voltage between them then yes, it is likely you have the short (and a simple ohmmeter check would confirm this with certainty).
Which would suck of course, so then you need either to rewind or to replace the xfmr.