ROUTINE MAINTENANCE
3.
SWITCH TEST (2B)
Remove
(5)
balls from the game before running the switch test. After entering the 2B code, the
keyboard display should read 8 00. The "8" indicates the switch group being monitored and the "00"
reports all switches open in that group. Each additional time the "B" button is pressed, the code for
the next group of switches being checked will appear on the left hand side of the keyboard display.
At the same time, in a game that is working properly, "00" will be displayed on the right hand side of
the keyboard readout, to report all switches open. This repeated pressing of the "B" button commands
the Main Processing Unit (MPU) to identify and monitor each group of switches sequentially (#8
thru #1, see chart) and return to group #8.
Each switch in the game also has a unique code, based on its group and position numbers. This
specific code will be shown only if that particular switch is closed when its group number is selected.
Switch codes appear in place of the "00" on the right hand side of the Keyboard display.
Example: If the Key Switch in group #8 is closed, the display will show 8 04.
When two or more switches in the same group are closed, the sum of all closed switches are
displayed.
Example: In group #8, if the Replay Button Switch is closed along with the Key Switch, the
display will show 8 05.
Note: The code numbers differ sufficiently to allow switch identification by subtraction of the
individual switch codes.
If the KDU shows any closed switches during the test described, locate and check for adjustment,
tracing associated circuits if necessary.
To complete the 2B routine, step the KDU to group #8 and manually close switches in the group,
one at a time. As each switch is actuated, the correct code should appear in the keyboard display.
Repeat with groups #7 thru #2 (group #1 is not used). If response is intermittent or does not occur,
clean contacts.
Caution:
Do
not burnish or file switch contacts or damage to gold plating will occur. Clean with
unused business card or equivalent only.
(Continued)
18
