Pinball Test Fixtures

Note: This page is a work in progress. Please help get it to a completed state by adding any useful information to it.

1 Introduction

Pinball test fixtures were designed to aid in the testing and repair of circuit boards in pinball machines. These fixtures were originally used by distributors who performed repairs and operators who serviced their own equipment. These fixtures are now commonly utilized by individuals experienced with board repair and who perform repairs frequently for games.

Most test fixtures primarily emulate a pinball machine's lamps, solenoids, displays, switches, and sounds. There are also various test sequences available, plus the ability to perform repetitious tests in order to "burn-in" a board.

The downside to these fixtures is that they are big, bulky, and tend to be rather expensive. In some cases, there is little or no documentation for the fixtures. Sometimes, fixtures were modified to accommodate boards, displays, or features that they were not originally intended to support. There is also little or no documentation on these modifications.

Since these test fixtures are designed to emulate the guts of a pinball machine, some collectors/technicians have built their own test fixtures using the guts of actual pinball machines.

Additionally, there are now some diagnostic tools available to help aid with circuit board testing and diagnostics while in-game or on the bench.

2 Test Fixtures

• Photos of various test fixtures (elkhartpinball.com)

2.1 Bally/Stern (Classic)

Bally took a different approach than most other manufacturers and built four discrete test fixtures for testing individual boards, which are commonly known as "Bally brown box testers".

2.1.1 Bally MPU Test Fixture

This test fixture can test Bally MPUs, however, the helpfulness of this test fixture in troubleshooting many problems is limited.

2.1.2 Bally Lamp Board Test Fixture

This test fixture can test both classic Bally and Stern lamp driver boards

2.1.3 Bally Solenoid Driver Board Test Fixture

This test fixture can test both classic Bally and Stern solenoid driver boards. It can also test early Bally sound boards, but that may require modifications.

2.1.4 Bally Display Test Fixture

This test fixture can test 6-digit Bally and Stern displays, and can be modified to also test 7-digit displays.

2.1.4.1 7-Digit Modification

Modifying the display test fixture to accommodate 7-digit displays involves adding some jumper wire, making some trace cuts, and couple components.

Parts needed:

• 30 awg wire
• 18 awg wire
• 20kohm 1/4 resistor
• SPDT switch

First, a couple of modifications will need to be made to the wiring between the .156" board connector and the .156" display connector.

The original .156" board connector. Note the position of the red wire with white bands.

Removed the red wire with the white bands and insert it into the open spot in the connector. Then, add a new wire in the spot from which the red wire was removed.

The modified .156" board connector. Note the position of the red wire with white bands and the new white wire.

On the .156" display connector, add the white wire and a jumper wire between the two pins. Two wires will need to be crimped into one of the pins.

The modified .156" display connector. Note the addition of the white wire and jumper wire.

On the .100" board connector, add two lead wires. These will be connected to the new SPDT switch. A new 1/4" hole can be drilled in the metal plate to add the switch.

The modified .100" board connector. Note the addition of the two wires.

Note the addition of the two wires and switch.

Note the addition of the new switch on the control panel.

Next, on the board, cut the indicated traces, add the resistor, and add the jumper wires.

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When using the test fixture, flipping the switch to the wrong setting will not cause any damage--it will simply interfere with the display blanking signal depending upon the header pin arrangement of the type/version of the display being tested and what the unused pins on the 6-digit display are tied to. Other than that, there are no ill effects for this modification.

2.1.5 Bally Sound Board Test Fixture

This test fixture is designed to test some Bally boards (-32, -50, -51, Cheap Squeak, and Squawk & Talk sound boards)

• http://elkhartpinball.com/BallyUnknownTester.htm
• http://www.pinwizman.com/Sound.html

2.1.6 Bally 6803 Test Fixture

This is a complete test fixture with switch and lamp matrices and is able to test the 6803 MPU, displays, and sound boards found in Bally 6803 games.

2.1.7 Stern SAM II Test Fixture

This is a complete test fixture with switch and lamp matrices, which can test Stern MPU-100 MPUs, lamp boards, solenoid driver boards, SB-100 sound boards, and 6-digit displays. It can also test comparable Bally lamp boards, solenoid driver boards, and 6-digit displays.

2.1.8 Stern SAM IV Test Fixture

This is a complete test fixture with switch and lamp matrices, which can test Stern MPU-100/MPU-200 MPUs, lamp boards, solenoid driver boards, SB-100/SB-300 sound boards, and 6-digit/7-digit displays. It can also test comparable Bally lamp boards, solenoid driver boards, and 6-digit/7-digit displays. It can also be modified to test some Bally sound boards.

3 Diagnostic Tools

3.1 Univeral/General

3.1.1 Switch Matrix Tester

• 64 switch matrix tester (Pinitech.com)

3.1.2 Chip Tester

• Inquisitor chip tester; for RAM, PIAs, and RIOT chips (Neoloch.com)

3.2 Bally/Stern (Classic)

• Switch matrix tester, cabinet switch tester, bench display, lamp board tester, driver board tester (Pinitech.com)
• MPU FixIt diagnostic test module, Bally only, (twobits.com)

3.3 Gottlieb

3.3.1 System 1

• Playfield switch tester (Pinitech.com)

3.3.2 System 80

• MPU diagnostic test ROM module (Pinitech.com)
• QuickScan80 Test Fixture, MPU diagnostic tester (greatplainselectronics.com)

3.4 Stern/Data East/Sega

• Switch matrix tester, lamp matrix tester, special solenoid input/output testers (siegecraft.us)

3.5 Williams

3.5.1 System 3-11

• Switch matrix tester, lamp matrix tester, special solenoid input/output testers, bench display (siegecraft.us)
• System 9-11 MPU tester (edcheung.com)

3.5.2 WPC

• Switch matrix tester, lamp matrix tester, Flipper opto board tester (siegecraft.us)

3.10 Zaccaria

• Switch, lamp, and solenoid testers (pinballsolutions.eu)

4 Custom/Homebrew/Bench Test Fixtures

4.2 Gottlieb

• System 1/80/3 test fixture solutions & ideas (flipprojets.fr). Located under The Projects > Materials, The Projects > Displays, and The Projects > Various > Built by our Readers

4.4 Williams

• System 3-7 custom test fixture, with build instructions (smokingcircuit.com), Video
• WPC-89 bench test fixture, with instructions (pinballrebel.com)
• Video of a custom WPC-89 test fixture (youtube.com, posted by ddstoys)