[Amps] how to check grid current

[R.Measures]

***   I would start by measuring the full-scale deflection of the grid-I 
meter with the amp unplugged, and recalibrate the meter if needed.  I 
would do the same thing with the plate/anode meter. 
-  If there are no glitch-protect diodes across the meter movements, I 
would add them.   Next I would measure the R of the 811A filaments to see 
if they are intact.  The reason I would do this is because I have seen an 
AL-811 with open filaments in three tubes.

>...

good luck, Alan