Hello from Maine,
Well I restored a converted 1985 Atari Gauntlet 

 Kinda, then MAME'd it. 
It was very beat up but bondo and semi-gloss black paint can help a lot 
 
 Also the sideart had to be restored with markers (it was painted over and when the paint was removed it was faded)
If you recall the Gauntlet control panel each player has two buttons, first is "fire, second is "magic / start". So the second button does double duty.
In MAME I set the player's second button to double as that player's "start", it accepts it in menu, but it doesn't work.
I had to change it so "button one" doubled as "start", and it works perfectly.
Am I am a bug or did I find a bug?
I don't have another (finished) arcade machine  at the moment to test this out on ...
I think this problem may be specific to the Gauntlet rom (ironically) ...
Thanks 

Craig
p.s. Here is a pic of it almost finished :
