Star Tech Journal

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DBJECTRDM
The maze PROM is 2C and the
charactor PROM is 2 E. CAO-CA5 to
the EPROMs come from the vertical
address timing section. 1 D and 1 C
are shift registers which manipulate
incoming data CD0·CD7 to the
appropriate outputs. The outputs
are multiplexed by 1 B and BIT 0
andBIT1 arefedtoPROM9Pinthe
color section.
The counter at 9H is operated
merely as a data transfer chip, not
as a counter. The CRB signal is
high during attracVcartoon mode
and low during the maze mode. The
thing 3 line is active only when
Junior is going up; it is low all the
other time. Most likely a problem in
this section would be a color
problem.
BOUND/AUDIO
AMPLIFIER
CDLDRRDM
This is where the color information
fed to the CRT guns is finally con-
solidated. Note two color ROMs 9E
and 9F. 9F handles the blue drive,
9E and 9F handle the green inten-
sity, and 9E handles the red drive
exclusively.
This section is the same as in Pac-
Man. Troubleshoot accordingly.
BVNCBUB
CONTROLLER
When the 2 H signal is low, the CPU
can address the RAMs. When high,
the sync generator gets to address
the RAMs. The "traffic cop" of the
data flow which keeps the CPU
from interfering with the sync
generator so they don't address
the RAMsatthesametime istheZ-
80 sync bus controller section. The
CPU can address any locations
except the RAM at 6A and 6C while
the 2H signal is high. If the CPU
tries to address the RAMs while the
2H signal is high, a decoder at 5F
(74LS139) pulls the wait line of the
CPU low placing it in a standby
state until the 2H signal is low. This
action restores the WREQ high
saying to the M PU "go ahead." The
same priority is given the sync
generator circuitry if the CPU is
currently addressing the RAMs
when the 2H signal goes high.
Therefore, the sync generator
addresses are given priority. This is
obvious because the most important
object is to maintain a stable display.
ELECTRDHDME '307-CBD
DC VDLTAGE MEASUREMENTS
BY KEVIN MOELLER, FIELD SERVICE TECHNICIAN, BALLY MIDWAY, FRANKLIN PARK, IL
ELECTRDHDME G07-CBO
DC VOLTAGE MEASUREMENTS
IC501
PIN
1
2
3
4
5
6
7
8
VDC
4V
1V
4V
3.5V
6.7V
11V
5V
10.5V
PIN
9
10
11
12
13
14
15
16
VDC
6ND
1.8V
12.5V
6.6V
PROTECTOR
BEAM LIMITER
BLANKING
X701
E 0V
B .4V
C 12.6V
X303
E 6V
B 7V
C 0V
X304
E 0V
B .35V
C 6V
NECKBDARD TRANSISTORS
X101
E 7V
B 6V
C 166V
ov
3V
6.6V
12.2V
X102
E 7V
B 6V
C 160V
X103
E 7V
B 6V
C 167V
TRANSISTOR DC VOL TAG EB ON MAIN BOARD
REGULATOR
SECTION E
B
C
X901
X04
120V E 120.6V
120.6V B 121V
145V C 145V
X902
E 7V
V 7.6V
C 71V
VERTICAL
SECTION
X401
E 45V
B 45.5V
C 112V
X402
E 0V
B .6V
C 44.5V
HORIZONTAL
SECTION
X501
E 0V
B .3V
C 67V
X01
E 0V
B.02V
C 120V
CUSTOMER
SERVICE
NUMBERS
TOKENS
CLOSE-OUTS
MIXED DESIGNS
* ALL
SIZES*
SUPER SAVINGS
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