From what I see on the schematics are these components:
(1) Service Outlet
(1) Fuseholder, Panel Mount style for 3AG style fuses
(1) 130 volt Varistor
(1) Line Filter, 120/240 volts, 50/60 Hz
(1) D.P.D.T. Power Switch
(1) Stereo Volume Control, 10k, Audio Taper
Be sure to check out Data East Service Bulletin # 27. It details a shock hazard with certain power boxes on the Simpsons pinball machines by serial number.
http://arcarc.xmission.com/Pinball/Stern%20Service%20Bulletins/sb/sb27.pdf