Check all of your solenoids to see if one is shorted, or just disconnect the connectors to the playfield and see if it still blows. You probably have a shorted drive transistor, too...
Shorted drive transistor? That would be an SE9302 right?
I did replace 2 of them, perhaps more are bad.
It blew the fuse in my working Baby, so I know my solenoids are all good.
Could one or some of the ceramic disc capacitors next to the SE 9302s cause similar issues too?
I just went through the same problem with my new Baby Pacman. I discovered a visibly burnt coil for a outhole kicker. I unsoldered the leads and the game ran fine. I replaced it and I decided to check out the driver board before powering it up since I figured that something else might be to blame and I did not want to burn out another coil. I found a bad driver transistor SE 9302 and also checked the resistor and diode above it. Turned it on and the 1 amp still blew. I then went farther upstream and got some puzzling readings on the CA 3081. Puzzling since I am not that good at testing components! I pulled it, installed a socket, and replaced the chip. IT LIVES. A great read for Baby Pacman owners - http://www.marvin3m.com/bally/babypac.htm