Yes, check PinWiki for the Transistor issues. There is some good information in the: 5.20.5 Coil Locks On regarding the transistor and pre-driver.
http://pinwiki.com/wiki/index.php?title=Williams_WPC#Solenoid.2C_Flasher.2C_and_Motor_problems
Another site that I found to be helpful when figuring out a recent flasher issue with my TOTAN:
http://techniek.flipperwinkel.nl/wpc/index2.htm (search for "I have a Stuck-on Coil (or Flashlamp), What should I Replace?")