Hickok Tube Tester Dead or Alive?

HeLLo friends!

I recently aquired a Hickok 800 Tube Tester and wanted to see if it worked. This unit is basically a newer version of the Hickok 600

I had some 6DJ8's, 6922's and KT88's at my disposal. All switches/settings were matched to each tube and I was ready to do some testing. Here's what happened >> Unit was turned on and when I inserted each tube for testing, the tubes lit up but the needle to take the measurements didn't move.

I'm not sure what part(s) is dead or alive. What do you think the problem is and who does tube tester repairs?

Thank you friends!
Isn't there a button that you have to push in addition to turning on the power switch? My Hickock 752 works like that anyway.
Do you have a manual? Manual, schematic, roll chart for 600 here. Should be helpfull for the 800.

I remain,

Yes there is a line adjust button to press Viridian. I think it might be the fuse or tube...I hope.

Thanks both for your help.