Whats up where the ball got stuck?
If there are switch and lamp connections then you may have shorted between the two with the metal ball... im guessing here of course.
Is the mini PF still raised?
Make sure your tilt switch isnt stuck on.
If the CPU led is on.. then the program is running... but this is really just a small part of the CPU board.
I would be disconnecting all boards and boot the CPU.
Then add the driver
Each time you advance one step turn game off and back on... so turn game off to add driver
Then add connectors one by one each time turning off the machine... you should be able to have all connectors off the driver and only connect CN17 at the bottom... this is ground path to all solenoids etc... with this connected you should be able to manually lift PF and lower by shorting tabs of transistors to ground.
Idea im thinking is to get the game to "normal" position and go from there.
If all is good with CN17 in place .. try adding the display connector... then the switch connectors... then lamps etc.
Do displays display normal with Driver off etc.
If ball got stuck where switch diodes are then test these etc
If we do one thing at a time, then we should be able to narrow the fault down to a particular area
