This is the procedure to activate the background sound in Williams Flash. Be default this sound is disabled.
1. Press 9 to enter diagnostic mode. The displays should go blank when this key is pressed.
2. Press 8 to enter test mode.
3. Press 7 then press 8 to see 01 in the credit display.
4. Continue to press 8 until you see 04 in the credit display and 31 in the match/ball in play display.
5. Press the 1 key to change the value in the first player display to 01.
6. Press F3 to save the change and reset the table.