Here are relevant bits of the schematic on ipdb.org.
Aladdins Castle score reel (resized).jpg
While the score reel is spinning and not stopping at zero, is the Score Reset relay or the 100 Point relay pulsing too? The Score Reset relay seems more likely. If that's the case the switch in the middle red box is closing and sending pulses to the 2nd Player 100 score reel. The switch just below it before the score reel should open at zero. Yours may not be opening or you may have a short on the solder tabs or somewhere else.
As for the Bonus Unit trying to reset repeatedly, what is the Bonus Score relay doing? Is it active too?
/Mark
