Star Tech Journal

10
STAR•TECH JOURNAL/JUNE 1982
A Regular Monthly Feature Technically Outlining a Newly Released Game
ATARI'S "DIG DUG"
By Joe Connor, Active Amusement, Philadelphia, PA
"Dig Dug" is Atari's latest video game, and one
of the only games that was not engineered or
designed by Atari, but instead is manufactured
UJ1der license from Namco Ltd. of Japan. At
initial glance, there appears to be little change
from this game and the games Atari designs
itself. The same basic cabinet and internal
electronic layout as used in previous Atari
games exists in "Dig Dug". Probably the first
giveaway that this is a Japanese design occurs
during the power up, when the ever popular
cross hatch pattern (like "Pac-Man", "Galaxian",
and "Super Cobra") flashes on the screen
during the reset mode. Closer examination
reveals the principle difference between this and
previous Atari games is the logic board, more
specifically, the use of the three Z80A micro
processors instead of a 6502A, the processor
used on all previous Atari games.
isolated for the monitor, 6.3 VAC for the coin
door lamps, and 36 V AC which inputs into a
halfwave rectifier on the logic board. The result-
ing -29 volts DC off this rectifier supplies the
ER (high score) prom. The transformer assembly
also has a 27,000 MFD capacitor and a bridge
rectifier (MDA3501) mounted on it to supply a
high current DC voltage. This + 10.3 VDC has
numerous functions . Primarily it serves as an
input into the +5 volt regulator circuit on the
audio regulator board. The + 10.3 volts also
goes to the utility panel for the left and right coin
counters and to the coin door for the left and
right coin lockout coils. The final destination of
the + 10. 3 VDC is pin E on the logic board
where it serves as the supply voltage for an LM
324.
The + 5 volts ( adjustable with a trimpot on
the audio regulator board) drives the I Cs on the
logic board and it also runs out edge pin R of the
logic board to the one- and two-player start
LEDs on the control panel.
Take note that there are no interlock switches
mounted on the coin or back doors. Anytime a
fuse is changed, the machine should be unplugged
or turned off. The on/ off switch is located on the
back of the cabinet, lower left side.
SYSTEM POWER
The power distribution is fairly simple to trace
out and similar to most Atari videos. The
outputs off the transformer include 120 VAC
SYSTEM POWER
120 VAC ISOLATED
MONITOR
I
ON/OFF
SWITCH
LINE
VOL TAG E
--1:
VOLTAGE
SELECT
BLOCK
6.3 VAC
- ,,
-
- . ,
.
TRANSFORMER
ASSEMBLY
10.3 voe
FLUORESCENT
TUBE
-
,,
Fl
F2
F3
F4
F5
F6
FUSES
120 VAC
10.6 VAC
12.5 VAC
36 VAC
36 VAC
6.1 VAC
7A SB
4A SB
20A SB
4A SB
4A SB
4A SB
COIN DOOR
UTILITY PANEL
AUDIO
REGULATOR
PCB
36VAC
.___
5VDC
.... ,
-
7
\I/
LOGIC
BOARD
+5VDC
-
,,
CONTROL
PANEL