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Repairing Williams System 3
to System 7 Pinball 1977 to 1984
(with help from Mark & Jerry)
Copyright 2002-2007 all rights reserved.
This document is a repair guide for Williams System 3, System 4, System 6 and System 7
pinball games made from 1977 (Hot Tip) to 1984 (Star Light), and includes the famous
Black Knight, Firepower, Gorgar and Flash pinball games.
Updates of this document are available for no cost at
if you have Internet access.
This document is three parts
(part one is here,
part two is here, and part three is
IMPORTANT: Before you Start!
IF YOU HAVE NO EXPERIENCE IN CIRCUIT BOARD REPAIR,
YOU SHOULD NOT TRY AND FIX YOUR OWN PINBALL GAME!
Before you start any pinball circuit board repair,
review the document at http://pinrepair.com/begin,
which goes over the basics of circuit board repair. Since
these pinball repair documents have been available, repair facilities are reporting a
dramatic increase in the number of ruined ("hacked") circuit boards sent in for repair.
Most repair facilities
will NOT repair your circuit board after it has been unsuccessfully repaired ("hacked").
If you aren't up to repairing pinball circuit boards yourself or need pinball parts
or just want to buy a restored game, I recommend seeing the
suggested parts & repair sources web page.
Table of Contents
- Experience, Schematics
- Necessary Tools
- Parts to have On-Hand
- Game List
- Different System Generations Explained
2. Before Turning the Game On:
- Game Assembly & the Black/White Connectors!
- Check the Coil Resistance.
- The Power Supply (Explaination, Testing, Fuses,
Bridges, Test Points, Modifications, Repair)
- Batteries, the Battery Holder, Battery Corrosion, and the 5101 RAM
- 40 Pin Interboard Connector (Dead Game or Random Lockups & Resets)
- Power Connectors (Dead Game or Random Lockups & Resets)
- Circuit Board Sockets (Dead Game or Random Lockups & Resets)
- CPU Board Upgrades (System 3/4 to System 4/6 ROM Upgrades, etc.)
- CPU/Sound Board Jumpers, ROM software, Flipper ROMs, DIP Settings.
- Driver Board Checks & Upgrades (Burnt Resistors, etc.)
- Testing Driver Board Transistors
- General Illumination Connectors (Burnt GI)
3. When Things Don't Work:
- Power-On Audit Mode, Funky Score Display Numbers (Battery/5101 RAM Problems)
- Fixing a Dead CPU/Driver Board (CPU LED codes, Test EPROM, Blanking)
- Diagnostics (Display test, Lamp test, Solenoid test, Switch test)
- Random Lockups & Resets: What Causes Them & Testing For Them
- Non-Working or Locked-on Coils/Flashlamps
- Lamp Problems (the Lamp Matrix)
- Switch Problems (the Switch Matrix)
- Score Display Problems
- Sound Problems
- Flipper/Drop Targets Problems & Upgrades
- Miscellaneous Oddities
Bibliography and Credit Where Credit is Due.
Lots of people contributed to this document, and I just want to
say, "thanks!" Below are a list of
the resources used in the development of this guide. Some resources/people
may have been innocently left out, and
many of the ideas in this repair guide are not original.
If this is the case, and an idea
is here that was originally yours, please notify me and I
will make sure to give you credit!
Some people question whether I wrote all this material myself. I did, but of
course like everyone, my repair techniques and ideas are gathered
not only from my own experience, but from work that
others in this hobby do and share at shows, on the
internet, etc. So if you're the originator of some
cool trick or tip in this document, and I'm not giving due credit,
just let me know and I'll add you to the list of contributors above.
- Mark Orthner (mark at techvantage.net), and his web page at
Many ideas, pictures, advice came from Mark's site (with permission). Mark was
instrumental in making this document happen, and contributed a great
deal to the cause. If it wasn't for Mark, I would have never written this guide.
Thanks Mark!! (or "damn you Mark!")
- Jerry Clause.
Jerry is probably pretty sick of me asking him a zillion
questions. He was indispensible in writing this guide.
- David Wagler, Des Moines IA (Dwagler at aol.com). David provided lots of broken boards
and parts that were used in the development of this guide. I could not have done
this guide without Dave's donated broken boards, wiring harness and displays!
- James Koempel, Keasnburg NJ, (j.koempel at verizon.net). James provided
circuit boards used in the development of this guide. Again, it would have
difficult to do this guide without his help.
- Jeremy Wilson. JW also provided a "box of boards" used in the development
of this guide. Once again, it would have been difficult to do this guide
without his help.
- Leon Borré and his system3 to system7 test EPROM at
Leon's test EPROM was great for diagnosing broken CPU/driver boards.
- Duncan "Scanbe" Brown. Duncan provided lots of tips and tricks. Did I mention
Duncan *hates* Scanbe sockets?
- Frank-Rainer Grahl" (frgrahl at gmx.net).
- Mr. Johnson and his web site at
Ray's postings and tips were most helpful.
- Tuukka Kalliokoski's web page at
Tuukka's web page was also very helpful in making this guide happen.
- Rob Hayes, who's advice and (lack of!) proof reading were very appreciated.
- David Gersic, who also did proof reading and provided some tips.
- John Robertson and his posts & tips helped mucho grande.
- "Solid State Flipper Maintenance Manual, Gorgor and later" (Tri-zone, Time Warp,
Laserball, Gorgor), Williams Electronics #16P-496-100, December 1979.
- "Solid State Flipper Maintenance Manual, Firepower & Later Games",
Williams Electronics #16P-497-100, March 1980.
- Pinball Liz Tech Reprints #1 to #6, August 1995 to August 1996,
for their tips and tricks.
* Return to the Pin Fix-It Index
* Go to Part One System3-7 Repair Guide
* Go to Part Two System3-7 Repair Guide
* Go to Part Three System3-7 Repair Guide