COMET CENTRAL

I have a 64 Cyclone tach that's in great shape but for the decal on the front screen.
Not quite sure how to remove the screen without doing any damage to the functioning components.
Do I unscrew from the bright trim ring at the front, or is it the screw through the back?
Does anyone have a diagram or experience in repairing or disassembly of the Falcon Sprint or 64 Mercury Cyclone tachs?
Thanks in advance!

I left you a reply on the HAMB, the stainless ring is not screwed on, it may be crimped from the back. I would contact the manufacturer or possibly a speedometer/ gauge repair shop, they might have the answer. As I mentioned the light bulb is the cause of the issue.
Jim