Pinball Repair Information:

Mark's Pinball Page - A general site about pinball, but his System 3-7 Troubleshooting and Repair is a great source of information

Marvin 3 Site - Another great site about the repair of ALL types of pinball machines.  Also includes other classic coin op machines.

Flipper Pinball Fan - A Belgium site that covers many aspects of pinball repair.  This site is where you can download the test ROM for just about any machine!

Pinball4You - A Swiss site that explains the conversion to use a System 7 driver board on System 6 Pinballs.  See this link for more information. 

firepowerpinball.com - A comprehensive site for Firepower Pinball.  Also includes other resources good for System 3,4,6, & 7 games, including updated manuals and schematics.

General Electronics Parts Sites:

Allied Electronics - Commercial electronics distributor. 

Digikey Electronics - Commercial electronics distributor.

Mouser Electronics - Commercial electronics distributor.

Futurlec Electronics - Electronics site with very good prices and MC6802 Microprocessors in stock

BG Micro - Electronics site with good prices and MC6802 and MC6821 PIAs in stock

Jameco - Electronics site that sometimes has MC6802 or MC6821 in stock