[Drake] T-4XC low output

[K4GM- George]

Here's my problem for which I ask your advice.

I can't get more than ten watts out of my T-4XC when using the 
internal PTO.  It is drawing at most 120 ma.  Increasing the loading 
won't help.   When I have it connected to the R-4C I can hear the 
SPOT signal at S3 but it was S9 when the rig was working 
correctly.   I cannot hear the SPOT on my Icom located 3 feet 
away.  If I place it in Tune or CW I can hear the signal at S9 on my 
Icom.  The T-4XC is connected to a Dummy load for these tests.

All voltages are within 10-15% on V3, V4 and V8  (mixer and driver) 
except that there is zero voltage on the grid of the mixer (should be 
.3v).  Resistances from tube socket pins are as in the manual except 
that the grid pin on the mixer reads about 950K while the manual says 
450K.  I have checked the resistors individually which feed voltage 
to the mixer and they are fine.

If I set the bandswitch to 20m and peak the RF TUNE in the 40 m 
range(as I have done more than once by accident when switching from 
40 to 20) the radio will tune to an output of 125 watts like it used to.

Any suggestions would be appreciated.  Also, does anyone know where I 
can find what the RF voltages should be at various stages in the xmtr??

Please help.   I have the excellent CD repair guide from K4OAH so am 
ready to tackle this one but seem to be going in circles.  This xmtr 
was my best one until it went south.

And, finally,  if I switch to the R-4C for frequency control the 
T-4XC works perfectly!!!

K4GM - George