13 year necro-bump.
When the subject of Asteroids screen flipping for cocktail cabs came up last month, I asked Haze if it would be possible to at least add the information about the jumper from J20 pin 7 to pin 19 (the "ground wire" paigeoliver mentions above) in the Cocktail cab harness and the associated screen flipping circuits (Q15, Q16, and Q17) in the "2b" schematic to the MAME driver info.
(opt2not made it easy to find the info thanks to the outstanding documentation in his
Rock on! Asteroids Cocktail Restoration thread
)
Haze replied he wasn't familiar with the asteroids driver, but relayed the request to the other MAME devs.
Just got word from Haze that ajrhacker submitted a pull request
here for player 2 screen flipping on Asteroids and Asteroids Deluxe.
Once the pull request is accepted, it will be implemented as a "machine config" option in the next MAME release.
Scott