06-28-2015, 07:43 PM
If you have the test equipment recommend Alan Douglas' book, it has good information in it about the calibration of almost any Hickok tester. Most of them employed the same circuit and associated voltages.
If not: http://www.alltubetesters.com/
Or: http://www.radiolaguy.com/info/tubeTesterRest.htm
If not: http://www.alltubetesters.com/
Or: http://www.radiolaguy.com/info/tubeTesterRest.htm