[Heathkit] Heathkit TT-1 Tube Tester Problem

[Harry Williams]

Hi....I am having trouble testing a 12BY7 on my TT-1 tube checker. I have tried testing 5 or 6 of them and when I pull the gm test switch the meter slams the right hand peg on all the 12BY7's. Other tubes seem to test just fine. I have gone through all of the operational checks and calibration procedures and everything looks ok. So I am wondering if the settings in the tube list are correct. I have the latest supplement (1978) and I do not see any updates in the settings for that tube. So I am wondering if someone else that has a TT-1 that has tested a 12BY7 can verify that the settings for that tube are correct.

Thanks and 73's
Harry
W0LS