clip

This is the second reason that Mars inner backglasses are super-rare: this tiny clip, and another one on the other side, are all that holds the inner backglass in place at the bottom. It's hard to get a sense of scale from this picture (I should've included a penny) but the lip on that clip is literally less than half a millimeter long.

 

So, a couple good bumps (as people are wont to do with pinball machines), and the next time the operator opens the backglass to replace a dead bulb the inner backglass comes crashing down.

 

This is a big part of the reason that I'm going to try to have my replacement inner backglass printed on plexiglass instead of glass-glass.

Done