[Central-Electronics] CE-100V Driver plate current

[Gordon]

In the Manual, it says to check the Driver 6BQ5 plate current without drive.
  It says it should be .36 volt. Mine is .29, but I don't understand 
exactly how I am supposed to get it up to .36.
The Manual says to change the "Ratio of the Bias divider resistor" ??
It would have been simpler if they had set it up like the 200V.
Can anyone help me out?
Thanks

73,
Gordon