6
STAR*TECH JOURNAL/JANUARY 1984
* CMOS NON-VIDEOS
INFO
* TROUBLESHOOTING
(PART 4)
*
WILLIAMS SIN/STAR BUG
* CINEMATRONICS DRAGON'S LAIR AUDIO HUM
By Mark "Bear'' Attebery, Vending International Corp., San Juan Capistrano, CA
In Future Tech Lesson #9, we looked at some seven-segment
LED ( or LCD) displays and I explained that CMOS I Cs are
easy to us, use less space, etc. What I neglected to mention was
that just about everything that most people want to do is already
available as a CMOS single chip or as a large chip with a few
discrete components. An example, you ask? Digital clocks,
meters, timers, test instruments such as frequency counters,
multimeters, and even home video games to mention just a few.
you get that far, if you haven't found the problem, it's time to call
the company's service department for help.
A very useful book to own if you're working with CMOS
chips ( or even if you just want to play) is the CMOS Cookbook
by Don Lancaster. It was first copyrighted in 1977 and was in its
seventh printing in 1982. There are literally thousands of LSI
chips that have come out since this book was written, but there
are enough "toys" in this book to keep you busy for quite a while.
I think you'll enjoy.
This month I have a couple of technical tips for the technicians.
On to the last part of the 4-part troubleshooting of non-video
games ...
On the second wave on the last ship, you need to have
acquired 20 bombs. Release all 20 and at least 13 have to hit
Sinistar. If you ship is destroyed before the 13th bomb makes
contact with the Sinistar, your game will go on FOREVER!
(Whoever said that we technicians didn't do any good by playing
the games?)
TROUBLESHOOTING NON-VIDEO
LOGIC BOARDS
1 A) If there are motors, lights, solenoids, or any other externally
mounted units that are operating when they shouldn't be or are
not operating whim they should. You've checked the trip or limit
switches, wiring harness, connectors, and the position of the
mechanism. Then the first thing that should be checked on your
logic board is the operation of whatever drives that external
device.
lB) To check any relays for correct operation, simply place your
o' scope on the trigger line ( usually the anode side of the diode
running across the coil). The trigger line is usually switched to
low ( or to GND) causing the relay to energize. If the logic is
correct and the function isn't, replace the relay. (If the cathode
side is switched, look for it to go from low to high.)
IC) Transistors are the easiest to check. Get out your $14.95
transistor tester that you bought at Radio Shack and test them.
lD) If your triac is receiving its trigger signal but no voltage is
evident across the output tabs, or if no signal is present but
voltage is being allowed to pass, replace the triac.
2A) If you're working with a digital sequential logic board,
simply use digital troubleshooting techniques. Using an o' scope
is much preferred to a logic probe for one basic reason: If a gate is
tested using an o'scope and its voltage is not totally high or
totally low, you'll see it immediately and not need to go any
further (unless you have a capacitive/resistive holder on that
leg).
2B) If yours is a microprocessor-controlled game, first check the
support circuitry using digital troubleshooting techniques. After
Speaking from a manufacturer's viewpoint and from past
experience, if you follow the first three parts of troubleshooting
and make no progress (unless you have the time to spare with a
down game), it's advisable to send the logic board to the
company for repair.
WILLIAMS' SIN/STAR
Now I'm not sure if this is a program error or if there was an error
in the game's logic board, but this is whatJoe Fite of Pizza Time
Theatre in Houston, Texas found:
If your game has this "feature", you may want to see if there
are any board revisions or EPROM exchanges available from
the manufacturer. Thanks, Joe.
CINEMATRONICS' DRAGON'S LAIR
Ron Robidas of South Service & Sales in Bloomfield, Connecticut
called this in to me:
If your Dragon's Lair goes bananas and a loud hum is
evident in the sound system ( shades of Defender!), the problem
is probably that one of the 7 vac sockets mounted on the coin door
for the coin door lamps have been bent and one is shorting to
ground. If you'll remember, this was a common problem with the
Williams Defender game a few years ago. The -5vdc circuit on
the power supply kept being blown out Well, the Condor ,power
supply that Cinematronics uses is so heavy-duty that no damage
was noticeable on this one unit that was called in to me.
Now, I know that I usually don't write tech tips on videos, so
if you have some info that you think is useful to other technicians
while working on a video, you can send your symptoms and
solutions directly to Star*Tech Journal. Don't forget to include
your name, and your company's name and address for proper
credit
As in the past, if you have a "find" or if you have a question
about non-videos, give me a call at 1-800-821-8990 or in
California, Alaska or Hawaii 714/661-6808.
Until next month, "Bear''!
(P. S. Check out the AMOA Non-Video Review in this issue.)