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STAR*TECH JOURNAL/OCTOBER 1983
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IECH'1(
JOU
The Technical Monthly
for the Amusements Industry
P.O. Box 1 065
Merchantville, NJ 08109
609/662-3432
OCTOBER 1983
VOLUME 5, NO. 8
Publisher/Editor
James Galore
Administrative Assistant
L.T. DiRenzo
Art/ Advertising Coordinator
Paul Ehlinger
Circulation Promotion
Linda Geseking
Layout
Dale Meloni Graphics
Contributing
Technical Writers
Todd Erickson
Don Becker
Mark "Bear'' Attebery
Sam Cross
Jim Bender
Howard Smith
Robert Russell
Peter Gurko
Lynne O'Connell
STAR*TECH JOURNAL, October
1983, Vol. 5, No. 8. Copyright 1983
by Star*Tech Journal, Inc. All rights
reserved. Address inquiries to: P.O.
Box 1065, Merchantville, NJ08109.
Phone: 609/662-3432. Subscrip-
tion rates: USA-$40.00. Canada·
$45.00. Other countries-$70.00.
Please remit payment in US funds.
STAR•TECH JOURNAL (ISSN
0739·1048) is published monthly
by Star•Tech Journal, Inc., P.O.
Box 1065, Merchantville, NJ 08109.
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this Journal may be reproduced
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articles herein are verified as much
as possible. However, any reader
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accepts no responsibility for its
advertisers' activities.
NEWS BITS/
PLASTIC EPROMs TARGET PRODUCTION APPLICATIONS
Responding to a dramatic shift in the market for eraseable, programmable, read-only
memories (EPROMs), semiconductor makers have begun to package EPROM chips
in plastic for use in end products as well as prototypes. Intel Corp. has introduced a
plastic version of its EPROM chip that stores 64K bits of information. Other memory
makers are expected to follow suit EPROM is a type of read-only memory (ROM)
originally developed for use in product development In contrast to random-access
memory (RAM), which is volatile, ROM retains stored data when power goes
off.Hence it has found wide application as a program storage medium in video games,
personal computers, and other consumer products. ROM, however, is unalterable once
programmed while EPROM can be reprogrammed after being erased with ultraviolet
light. Because of its high initial cost, EPROM was once confined to prototype
development where program changes are frequent. But as prices have fallen,
manufacturrers have increasingly used EPROM in end products to avoid having to
switch memories in mid-stream. In fact, end products now account for 80 percent of
EPROM production. Fast-rising EPROM demand - estimated at $900 million
annually - has outpaced supply. The new Intel EPRO M is electrically identical to the
development version, but comes in a windowless plastic package rather than a
fenestrated ceramic one. The new package is easier and cheaper to make and has no
need of a window, since production EPROMs are never reprogrammed.
CINEMATRONICS'
DRAGON'S LAIR INTERMITTENT VERTICAL ROLL
By Howard M. Smith, B&B Vending, Dallas, TX
All of our Dragon 's Lair games have exhibited an annoying tendency for the picture to
"roll" vertically during the first few frames of each episode. This is very distracting and
if the game is set for increased difficulty, the player can be dead before the picture stops
rolling.
• Changingthe0.33 ufcapacitorC105 on theNTSC decoder board to a valueof0.01
uf will stop this vertical instability completely.
This vertical roll is due to a temporary loss of sync caused by an incompatibility
between the disc player and the sync separator circuit of the NTSC decoder board.
When the disc player is searching for a particular frame, it blanks the video, but
maintains the sync signal so that loss of sync should not occur. The problem stems from
the fact that the DC level of the sync signal changes when the video is blanked. This
change interferes with the normal operation of the sync separator and several sync
pulses are lost
Reducing the value of coupling capacitor Cl05 solves the problem by making the
circuit more tolerant of low-frequency changes in the DC level of the sync signal.
STERN
FRENZY POWER-UP CREDITS
By Robert F . Russell, Williams Enterprises, Inc., Enfield IL
Subject: Frenzy ZPU 1001 PCB
Problem: Random credits while game is in power-up mode.
It recently came to our attention that some of our Frenzy games were being played for
free in certain locations. Free games were being achieved by turning the power off and
then on again and quickly depressing the one player start a number of times while game
was in its power-up mode.
Solution: We found a number of games in which the CPU was a Z80N4MHz. We
solved the problem by putting in the slow Z80/2.5MHz which is what the schematic
calls for.
COIN·OPALARM SYSTEMS BY CAPRICORN
Capricorn Enterprises of Midwest City, Oklahoma, now offers a line of self-
contained alarm systems. The CAS-1 is designed for fit all commercial video
games, pinballs and jukeboxes. The CAS-2 is designed to fit pool and foosball
tables, cigarette and other vending machines.
The Capricorn Alarm Systems are easily installed and provide dependable,
tamper-proof protection.
For additional information and orders, call or write: Capricorn Enterprises,
P.O. Box 50021, Midwest City, OK 73140. Telephone: 405/732-7570.