Hi All:
I have a HICKOK 539B TUBE TESTER. It working in excellent condition.
Few days ago , I just change the 83 rectifier tube. Then i test the
power tubes or preamplifier tubes. The GM read value over the micromho
metter. I change the original 83 tubes. The same effect.
Anybody can give me any better solutions for the problem I would be
thankful. Please e-mail

liu