If you wiggle J115 and the lamps work, then it's likely a cracked solder joint on the board.
See: http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#General_Illumination_Problems
LMK if you need help fixing it. See the "contact" link below.
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
http://www.PinWiki.com - The Place to go for Pinball Repair Info