I recently got a Space Invaders pin to repair for an operator who never used it on location. It is in excellent condition
and has no playfield wear. The mpu board has a lot of battery acid damage and the acid dripped down to the
lamp driver board below it. The corrosion prevents me from being able to desolder the corroded SCRs to replace
them. The game is also missing the solenoid driver board. I already have the replacement boards so that's
not a problem. In return for repairing the game, the operator gave me a LOT of boards, parts, manuals, rubber
rings, fuses, lamps, etc. He is retiring so he doesn't this stuff anymore. He might decide to sell the game. I already
have 2 widebody games (Paragon and Future Spa) so I really don't have room for this game. Still, I might make
room for it because this is the best Space Invaders I've seen in the last 20 years.

I got a Space Invaders pinball from an operator who bought it new but never put it on location. It was seldom used
and then a board was removed from it to repair another game. After that, it sat in storage for years until I got it.
I replaced the missing solenoid driver board and shopped it out. One thing I noticed is that it does not have a
serial number stamped on the side of the cabinet or on the head. There also were no serial numbers on any boards,
the wiring harness, or inside the cabinet. I don't see anything about it that would indicate that it's a prototype.
It doesn't look or play any differently than any other Space Invaders I've seen. The operator said that sometimes
he would get a prototype when he bought new games but he doesn't remember anything about this one. So why
wouldn't this one have a serial number? Even prototypes have some kind of serial number.