[Boatanchors] Hickok KS-15560-L1 tube tester calibration procedure needed

[HL1FB]

Hello;

     I acquired a Hickok KS-15560-L1 tube tester and I am looking for a service manual or a 

calibration procedure for it.  The tube tester looks similar to Hickok 539 series and it has a 

name plate written 'Made for Western Electric by Hickok'. 

I found a manual for it and a calibration pricedure for 539B/C models but it seems they do not exactly apply

to KS-15560-L1 model.

I repaired TV-7 tube testers many times but this model is new to me. The tester is working but tested values

are much higher than they should be. Could someone help?