[R-390] Line Level Meter not working...Help a newbie!

[R. David Eagle]

Hello all,
I have just started back up restoring my Motorola 390a after taking a break from it after moving to a new QTH.  I have gone through it pretty well and re-tubed it and deoxed what I could.  The receiver seems to receive good, but I noticed that my line level meter doesn't move a bit.  The carrier meter seems to function OK with received signals.
Is there a good way to test the meter or is there something else I can check in to?  Might be looking for a replacement..???

Thanks in advance for the help!
Dave