Avo vcm mk1

[Bushbaby]

I havent used this in quite a while. Of course, I had forgotten to use the reset button in the event of a faulty valve being tested. The meter light is of course working having pressed the reset button. However, I'm not so sure of the accuracy of this unit - every valve anode test result that I evaluate appears low to that shown in the avo valve data manual. I was aware when I bought this that it had a problem with the negative grid volt pot being uncalibrated which doesn't help at all.

I'm not sure how to proceed any further at this stage. Any help would be most welcome.

Many thanks

Rob