B&K 700 Erratic meter movement.

[SwizzyMan]

Hi all,

I am currently in the process of restoring a B&K 700 tube tester. I have replaced all electrolytic caps and have calibrated the unit. I have noticed that the meter movement will swing erratically when reading a test result. This only happens when I try and read transconductance results. The needle will jump from side to side whenever I try and read the test result. It doesn't swing more than about a centimeter to each side. Any ideas on what could be happening here? I have the same problem with my 707 tube tester too. I wonder if anyone has come across this before.