Quoted from LTG:Mist ball.
Optos in the pocket on either side or across the playfield aren't working.
http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Opto_Switches This will help you understand the optos.
Look at over all condition. And price. Hard to clean areas clean or dirty ? Boards in the head look good or hacked to death and battery damage on cpu ?
Be fair in your estimation too. Don't expect a $5K game for $1K.
LTG : )
BSD not a 5k game. With this feature not working i would say 3-3500.