Play Meter

Issue: 1979 March 15 - Vol 5 Num 5

An easy-to-build
Gottlieb prom tester
By Jim Calore
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Gottlieb Prom Tester
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This easy-to-understand , easy-to-
build Gottlieb Prom Tester will detect
any memory failure due to bad
addressing or incorrect data outputs
in seconds .
This is done by comparing the
suspect prom with a known good
prom . The results are known im -
mediately!
This will certainly be an invaluable
piece of test equipment to add to
your shop . It eliminates guess work
and will find heat related failures
also .
CIRCUIT EXPLANAT[ON
A 555 timer chip, employed as a
free -running oscillator , serves as the
master clock . The output of this clock
is fed into a chain of counters to
obtain the prom addresses.
By addressing both proms sim-
ultaneously , their respective outputs
at any address should be identical.
The error detecting circuit will pick up
any difference , stop the clock , and
activate the error lamp.
If the prom under test is good , the
test cycle lamp will activate and the
test will automatically start again . The
reset switch will start the addressing
from zero count.
If you suspect a heat problem , just
led the prom recycle continuously
until its operating temperature is
reached .
CONSTRUCTION
This circuit can be built easily on a
4 1 h-by 6 -inch circuit card , available
in most electronic stores . [t would be
advisable to use sockets for all the
[C's . For the prom sockets use
low-insertion type sockets to facilitate
easy removal .
All [C's used are common , easy to
obtain , and inexpensive .
NOTES AND MODIF[CAT[ONS
The clock circuit can be adjusted
for a slower scan rate by increasing
the valve of the resistors and! or the
capacitor on Pin 6 .
The error LED will be activated
when the tester stop-go switch is in
the stop position . This checks the
LED before running the test.
PARTS LI ST
IC ' s
555
7493
7486
7402
7408
1
3
1
1
1
PLAY METER . March. 1979
Sockets
8-PI N
1
l 4-P IN - 6
18-P IN - 2
Lo-in s ertion
Resistors
470
3
270
1
lK
4
LEDS
2
(Green, Red)
CAPS
. 01
2
Switches
1
Togg le
Push-Button
1
Misc .
---
Hook-up Wire
Circuit Board 4 ~ " x 6"
Provid e +5V and GND Taps
57
Living in
the fast lane
Ramtek is introducing a one -
player driving game called GT
Roadster .
Among the game's features are a
four-speed stick shift , a simulated
system using a super 8mm film
cartridge , and authentic engine and
crash sounds .
Operator-selectable options in -
clude extended play , high score to
date for a free game , and easy,
medium , or hard play modes .
GT Roadster measures 72 inches
high by 27 inches wide by 48 inches
deep . Total weight is 350 pounds .
Six-digit
counter
The new Redington Model 152
counter is an accurate yet inexpen -
sive six-digit , non -reset , electro-
mechanical counter made in the
United States and designed for use in
coin operated vending machines ,
photo copiers, car washes , electronic
games , and lease equipment.
Plated steel frame assures rugged-
ness and long trouble-free operating
life . Trim one-piece cover dis-
courages
tampering .
Operating
mechanism , incorporating precision-
molded wheels and pIniOnS , is
maintenance free . Arranged for
base , rear , or behind-the -panel
mounting , the Model 152 is designed
for operation at a wide range of
standard AC and DC voltages .
Special voltages available on request .
Operating life is in excess of 3 million
counts on AC , 5 million counts on
DC.
58
Space
Wars'
encore
Cinematronics , Inc . of EI Cajon ,
California , has announced the intro-
duction of its latest 3-D action game ,
Starhawk .
Starhawk , like its predecessor-
1978's big hit , Space Wars - will
feature a Vectroscan monitor system
and realistic space action . Unlike
Space Wars , Starhawk can be played
by one or two players .
As the game begins , players have
the point of view of being in an
orbiting space station over a re -
volving planet. Enemy space ships
appear from deep space - first as
small specks , then grow larger as
they approach . Enemy ships ap-
proaching from behind will first
appear large , then diminish in size as
~hey zoom off into deep space .
Like the captains in such recent
entertaiment hits as "Star Wars ,"
"Star Trek ," and "Battlestar Galac-
tica ," Starhawk players will control
their sighting and firing by the use of
joysticks. Each joystick moves its
corresponding sight in all directions
across the screen, enabling players to
sight in the enemy ships and blow
them out of the sky with laser beams
fired by buttons on the joystick.
As an added feature , a "killer
ship" appears periodically on the side
of the player with the highest score .
A player who fails to hit the "killer
ship" will lose pOints from his score .
This feature helps keep the scores
closer, insuring more intense com-
petition and higher collections .
As with Space Wars , Starhawk will
be on Cinematronics' Vectroscan
monitor, which produces a well-
defined picture . Exploding ships
send debris in all directions, and the
3-D effects guarantee a player appeal
that shows up where it counts
most - in the cashbox .
PLAY METER , March, 1979

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