[Kenwood] ts-530sp tube replacement

[dave@fortenberry.com]

I recently picked up a nice ts-530sp (my second) and
noticed that the output seemed low. Confirmed with two
different wattmeters, even did the math
voltsXampsXefficiency(55%), which agrees with the
wattmeters. It runs 800 volts under load, and even with
a fresh set of 6293's (ruggedized 6146B) I still only
get about 90 watts out (@230ma), both full CW carrier &
PEP on SSB, all on 40 meters. Up on 10 meters, where I
neutralized the tubes, I can just squeek 50 watts out
with no measurable ALC action at all (normal ALC on
lower bands). The 12by7 driver is also a high testing
new tube. Any ideas folks? I'm hoping to get a regular
service manual soon, but in the mean time... any
ideas?? Thanks & 73 de NA6DF