[R-390] Need Meter Repair Help

[Scott, Barry (Clyde B)]

I recently acquired an ME-26D/U VTVM.  It is in excellent shape except the meter movement itself.  The pointer drags against the dial plate ever so slightly near the zero-volts end.  I took the meter out expecting to be able to open it and adjust the needle, but when I got it out of the box, I found that job to be a little more complicated than I first thought.

This meter has a ring that locks the back cover of the meter to the bezel/outer face plate.  This is held together with a locking ring.  The ring has four small slots that I assume provide the means for a special tool to unlock the ring by twisting it about 10 degrees.

The problem is I don't have a tool to unlock the ring.  The shell is approximately 3.7" and the ID of the slots is about 3.8" making the tool that would be used to unlock this ring pretty special.  Does anyone have experience with this type of meter?  Any chance of anyone having such a tool to unlock the ring?  Can it be done with a small punch and a hammer without hurting the meter?  I hesitate to try this, but it might my only resort.  Any suggestions on a makeshift tool to unlock it?

Any meter-rebuilding experts out there?

Thanks,

Barry(III) - N4BUQ