CR161 calibration
 

I would like to see if there is a calibration procedure for this CRT tester.
I find it easier to use than my CR-70, but I get different results between the two. I "think" the CR-70 is more accurate as is, so I am wondering if there could be a problems with the CR161. I recently replaced a burned out 1k power resistor. I did check the filament supply voltage under load with a DMM and its right on the nose. I have the little book but its just socket and bias settings.
I am assuming there is some kind of adj to get the correct reading of current thru the tube.