Stern Pinball AC/DC Service And Operation Manual page 35

KNOCKER TEST
To initiate, from the diagnostics menu select the "KNO-CKER" icon. The digitally remastered "knocker" is sounded.
The knocker sound is used to alert the player if they have recieved a special replay or a credit from the Match Award
feature. Press the black [SELECT] button to activate the knocker. To return to the diagnostics menu, press the green
[BACK] button.
SOUND/SPEAKER TEST
To initiate, from the diagnostics menu select the "SPKR" icon.
This system produces true digital stereo sound from backbox and
cabinet speakers or "mono" on the cabinet speaker (when used
by itself). This menu is provided to allow the technician a simple
method of testing the speakers if rewired or replaced.
Upon entering the Sound/Speaker Test, you will notice the dot matrix display
indicating the first option of available music and/or sound(s) in this test. Press
the red [+/>] button to cycle through the available music and/or sounds and
press the black [SELECT] button to play the option shown in the dot matrix
display. Press the green [BACK] button to exit.
1. Check each speaker for polarity markings. If the speakers have polarity markings, verify the backbox speaker RED-BLK wires
and the cabinet speaker YEL-BLK wire(s) are connected to the negative (-) terminal.
2. Disconnect the speaker output connector J10 (AUDIO) from the CPU/sound PCB (in the backbox) and connect a 1.5v battery
across each speaker pair one at a time while observing the speakers.
3. Make sure the positive (+) battery terminal is connected to the positive lead [J10, Pin-2, CH A+] (RED-WHT) or [J10, Pin-4,
CH B+] (YEL-WHT) each time. As the connection is made, check speaker cone movement; proper connections are indicated by
outward movement.
BEGIN BURN-IN
To initiate, from the diagnostics menu select the "BURN" icon. After selecting this icon, the burn-in test will start. En-
sure the power interlock switch is pulled out if testing with the coin door open (required for coil function). Upon enter-
ing Burn-In Test, the game will exercise all CPU I/O functions: Dot Matrix Display Test, Coil Cycling Testing, All Lamps
Test, and Sound/Speaker Test. Press the green [BACK] button to pause and to view cumulative burn-in minutes. Press the green
[BACK] button again to return to the diagnostic menu.
SPEAKER PHASE TESTING
Connections to each of the speakers are polarized and
each must be connected appropriately for the best
sound quality. If one speaker has the positive and nega-
tive connections reversed with respect to the other, bass
frequencies will not be produced properly and the overall
sound quality will be poor. To test for proper speaker
phasing, use the Sound/Speaker Test to cycle though
the available music and sound. If the sound is not
balanced or doesn't sound correct, check the speaker
wiring.
AC/DC LUCI MANUAL 500-55C8-01
SERVICE MENU SYSTEM
35