If the meter is pegged when off then the meter needle is likely stuck.  Try tapping on it.  For the meter to go extreme like that I suspect the output tube on that meter is bad.  I've had tubes fail with a similar result but not with a stuck meter.  The stuck meter by itself won't damage anything but you really can't safely run the amp until you can properly bias the tubes.

You can always open the amp, pull the meter and open the meter to get it unstuck but you may not feel comfortable doing that.  I've pulled my meters before to avoid an expensive trip back to Steve for something I was comfortable addressing myself.