[Drake] T-4XC Plate current not rising bad finals?

[Frank Castelluccio]

Hello,
 
I recently aquired a T-4XC and the AC-4 supply. I
rebuilt the ac4 with the heathkit shop upgrade kit and
all viltages are good.
 
I am having an issue with the T-4XC though, upon
tuneup I cannot get a good indication of plate current
(doesnt even get to half scale with the gain all the
way up) and no visible dip.
 
When I try to set the bias I can get it to spec
however the pot is all the all the way up and the bias
voltage is about -42 volts. 
 
I swapped in a new driver tube and no difference. I
verified HV on the final plates.
 
I did test the 6JB6's on a tube tester and the test
good, perhaps this is not a good way to tell?
 
Can anyone offer any suggestions as to how I may
troubleshoot this and determine if the finals are
indeed shot?
 
These tubes are expensive and I dont want to buy a set
and ruin if the rig is faulty.
 
Thanks in advance,
 
Frank



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