Basic HTML Version
486
Table
4.
Typical Voltage Measurements
METER
MEASURE
TYPICAL
VOLTAGE
SETTING
ACROSS
READING
Unregulated
+SOV dc
(+) FS
+llV de
Logic Supply
(-) Ground
Logic B+
+IOV dc
(+) 3JS-I
+S.IV dc
(Gray Lead)
(-) Ground
Lamp Supply
+SOV de
(+) F3
+18V de
(-) Ground
Solenoid Supply
+SOV dc
(+) F2
+40V de
(-) Ground
Display Voltage
+250V de
(+) 3J5-4
CAUTION
+100V de
(Brown-White lead)
HIGH
(-) Ground
VOLTAGE
-250V de
(+) 3J5-3
CAUTION
-100V de
(Orange and White-
HIGH
Black Leads)
VOLTAGE
(-) Ground
General
IOVac
(+) Fuse Card Fuse
6.3Vac
Illumination
(-) Fuse Card Terminal
Slave Display Board
Proceed as foDows:
1. Turn the game OFF.
2.
Ul\Plug the cable connected to the board.
3.
Remove the four nuts and lockwashers that secure the
board to the nylon spacers on the insert door and
remove the board.
4. Position the replacement board on the spacers and
secure it using the four nuts and lockwashers removed in
step 3.
5. Reconnect the cable unplugged in step 3.
6. Turn the game ON and perform display digits test in
accordance with procedures provided in Section 5.
Sound Board
When replacing the Sound Board, the replacement board
must be checked to make sure it has Sound ROM I installed
and has jumpers for ROM operation.
In addition,
modification may be required to
jhe
Sound Board. Two
areas may require modification.
The first reduces
susceptibility of the Sound Board to noise and consists of
idding two resistors and a jumper. The second improves the
quality of the sound at the speaker and consists of changing
two resistor values. Proceed as follows:
I. Turn the game OFF.
2. Unplug the three cables from the Sound Board.
3. Remove the four screws and star washers that secure the
board to its mounting bracket and remove the board.
4. If the replacement board is not equipped with Sound
ROM I, remove the ROM from the old board and insert
it into the replacement board. Make sure that
the
notch
in the chip is at the right side.
S. Refer to Figure 9 and check the jumpers on the
replacement board. If the replacement board is not
jumpered as indicated, remove the four jumpers from
the replacement board and connect four new jumpers.
6. Inspect the replacement board. If it is equipped with two
fuses or if the modification indicated
10
Figure
9
have
already been made, proceed to step II.
7. Connect a jumper on the solder side of the board
between pins 39 and 40 of IC3.
8. Obtain two 10K, 10%, \4-Watt resistors and connect
them as indicated in the unused IC pad. This completes
the modification to reduce susceptibility to noise. Steps
9 and 10 improve the sound quality.
9. Unsolder and remove Rl4 and R23 (lOOK).
10. Obtain two 4.7K, 10%, \4-Watt resistors and solder
them in place of the resistors removed in step 9.
11. Position the replacement board on its mounting bracket
and secure it using the four screws and star washers
removed in step 3.
12. Reconnect the three cables unplugged in step 2.
13. Turn the game ON and perform the Sound Board Self-
Test procedure.
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