Tempest Monitor overheating

I was working on this headache awhile ago, and finally had to walk
away from it to get some other projects done. Did Tempest have a
cooling fan in the cabinet by any chance? My monitor is overheating
and the spot killer comes on after about 10 min.. I had the game on
the other night, and without the glass and the back door on the
cabinet, I played for about 2 hours without trouble. Last night
figuring I fixed it, started to put it back together and now it over
heats.

So far...

 I've had the game board rebuilt
New Big Blue
Reb. ARII board
New Bridge Rectifier
Rebuilt the monitor with Bobs Deluxe kit including HV cage
All voltages from the ARII are good.
B+ was adjusted to 181Vdc


The heat is coming from the side of the monitor with the 4 transistors
mounted to it. The HV cage area isn't that hot, so it has something to
do with the 4 transistors..

Any suggestions on where to look next?