Remember, electrolytic and tantalum capacitors are polarized. Make sure you are installing them correctly. Same goes for the voltage regulator.

Here is some repair info:

http://www.pinwiki.com/wiki/index.php?title=Bally_Home_Models

Here's a picture of a rebuilt series 2 power supply board you can compare to:

http://www.pinwiki.com/wiki/index.php?title=File:Bally0614-00912.jpg

You'll need a good magnifying glass to read the markings on a dipped tantalum capacitor. The printing and polarity markings are very tiny.

Check for a shorted diode on power supply board.

Solenoid driver transistor must be bad for that coil.

Here's a picture of of the layout of series 2 cu boards:

http://www.pinwiki.com/wiki/images/8/83/Series_2_Layout.JPG

Yes it is the driver transistor (S3) next to that lamp socket.

http://www.pinwiki.com/wiki/index.php?title=Bally_Home_Models#Solenoid_problems

Transistor S3 controls left slingshot and transistor S4 controls right slingshot.

It could be.