Williams Test Panel Information

I created a diagram of how the wiring runs to the test panel switches on Williams classic video games. I was inspired to do this for one of my customers that had issues with their buttons working.

For additional pinout information from the ROM board please download any drawing set.

So here’s some tips for how to use these buttons:
The Auto Up button is an on/off switch rather than a momentary switch. Depending if it’s in Auto Up or Manual Down will result in different functions. The Advance switch is effectively the “Enter” key, or more specifically it can enter menus or progress through them. High Score Reset is exactly what its name implies, press and hold it in game mode to reset the high scores. Now I’ll explain how to enter 2 modes: Settings mode and Test mode.

To enter Settings mode on games Stargate and later, leave the Auto Up switch in its up position, then press Advance. The very first page will always be Bookkeeping Totals, which consists of earning statistics and other game-specific audits. On Stargate and later games you use game controls to cycle through menus and changes options.

NOTE: Game difficulty options vary from Extra Liberal 0 (Easiest) to Extra Conservative 10 (Hardest).

Stargate has settings on 2 separate pages unlike other later games (Deeper gameplay options!):

Robotron and later games were more streamlined:

Defender had a more primitive audits/settings much more inline with Williams pinball; the Audits come first and then the Adjustments.

Navigating Audits/Adjustments on Defender is handled entirely with the test panel. With Auto Up, pressing Advance progresses forward through Functions in Audits/Adjustments. With Manual Down, pressing Advance will go backwards through Functions in Audits/Adjustments. To change Adjustment settings press High Score Reset. eg. Function 17 Free Play use High Score Reset to change option 0 to option 1 (Enable Free Play).

To enter Test mode on all games, press the Auto Up switch into the Manual Down position and then press Advance. Each game will cycle through tests in order of: ROM test, RAM test, CMOS test, Sound test, Input test, Color RAM test, and then Video test patterns before progressing to Bookkeeping and last Settings. The Auto Up switch must be in the Up position and press Advance to cycle between tests. NOTE: The RAM test will run indefinitely until pressing Advance to progress to CMOS test.

Stargate and later games feature a special burn-in test called Auto Cycle, it’s listed towards the bottom of the [last] Settings page on these games, change it to option YES and press Advance to initialize Auto Cycle mode. This test will continue until you press the Reset switch on the MPU or power cycle the game.