0
I~
'/"'4w"'.,..,.
6
12
0
0
0
0
0
0
0
Figure 2
By Zac Oliver
General l/lumination Vol t age
Reduction on Williams Flipper
Games:
Application
The nominal 6 .3 VAC used for
general illumination in flipper games
can typically be as much as 7 VAC
with high-line conditions. This higher
voltage decreases the lifetime of the
general illumination bulbs . To
correct this problem for areas that
have high line conditions, a modifica-
tion has been developed to lower the
typical AC voltage by about 1 VAC.
Material required: bridge rectifier
(35A , 100V), 8xl" screw
Procedure: (refer to figure 1)
1. Mount the bridge rectifier to the
right of the lamp and solenoid
rectifiers-
a . Use a center punch to mark
mounting hole location;
b. Drill pilot hole to a depth of
approximately 3/ 8H using a 1/ 16H drill
bit;
c. Secure the bridge to the back-
box using #8x1 H sheet metal screw.
2 . Unsolder the yellow wire from
the bottom of the 20A fuse clip and
solder to the bridge positive ( +) and
negative (- ) terminals .
3 . Solder the yellow wire attached
to the bridge AC terminal to the
bottom of the 20A fuse clip.
I II OUNT Ill~
RECTifiER
FUSE CAIIO
2 OISCOOIHECT FIIOM
IOTTOW OF 20A
FUSE CL" AN D
IOUIEII TOMOGE
YELLO W
YELLOW
6 BR 3
figure 1
Cinematronics Vec tor Monitors
Burned 47 ohm Resistors in Current Amplifiers
power transistor are operational :
A common failure of the current
this is best accomplished by dis-
amplifier, especially on older
monitors, is blowing of circuit break-
connecting the molex plug and
ers CB1 and CB2 accompanied bu
checking right at the pins. The row of
pins with the lone male pin always in-
burning of 47 ohm resistors around
the power transistor molex .
dicates the 2N5878 driver . The row
of all -female pins indicates the
The power drivers should not be
unplugged during game operation ,
2N5876 power drive .
Check on boards drivers Q108,
or the same resistors will be over-
Q109, Q 208, and Q209 with ohm -
driven and eventually burn . Check
meter or in -circuit transistor tester.
for cracked solder around the molex
pins. W ith an ohmmeter or
Upgrade 47 ohm resistors from ~
transistor tester, verify that the
watt to \!:!-watt if not so eq uipped . •
~ ~
c.u -r
Ht:.f'C.
0 ,,
13
~
0
0
0
0
D
D
.
0
Service Bulletin:
Cinematronics Vector Monitor
DAC-80 Modification
In order to insure prolonged re-
liability of IC1 (LF13331) on Cinema-
tronics' monitors, a current-limiting
resistor is being added to the outputs
of the horizontal and vrtical DACs.
This is a recommended retrofit for
all existing systems.
Add one each 820 ohm, ~ watt
resistor to underside of the board
between pins 15 and 18 , as per figure
2. Be sure to sever trace at the
indicated position.
This modification does not apply
to units equipped with analog switch
substitution board .
Special Wells Gardiner Monitor
Adjustment to Preuent Distortion on
Space Encounters
1. Measure collector voltage at
transistor Q203 and adjust to
64 VDC using the video bias pot R206
(with contrast control at minimum
setting) .
2 . Adjust brightness control to a
minimum setting (counterclock -
wise) .
3. Adjust contrast control to 20
degrees of maximum (clockwise).
Contrast Adjustment on Rip Off
There may be too great an
intensity difference between the fuel
cells and the ships if a R ip Off game is
positioned in a low ambient light
environment. This contrast problem
can be solved by the insertion of a
variable resistor in the intensity net-
work located in the monitor PCB
board .
Replace RlO (5 .6 K) with aSK ohm
potentiometer . This will allow the
fuel cells to be adjusted to an
acceptable level.
•