Star Tech Journal

STAR*TECH
January 1996
Journal
16YEARS OF
STAR* TECH ON
CD-ROM
DESCRIPTION OF PROGRAM
All previous editions of STAR* TECH
journa4 Volumes 1 - 16 (March 1979 -
February 1995) have been scanned onto
a single CD-ROM disc with a custom
Multi-Media Microsoft Windows Program
which places thousands of articles at the
fingertips of coin-op game technicians.
... continued from page 8
lector directly to these parts.
While you are at it, check any
diode you see in the general vi-
cinity of the flyback. If you re-
place the HOT, everything else
seems OK, and it still takes out
fuses or burns up the new HOT,
we have to suspect the flyback.
If the main fuse blows but not the
secondary fuse, then the fault is
likely in the power supply.
work fine for this testing, since we
are looking for short circuits in
the transistor. Keep in mind that
some other part of the monitor
could have caused the power
supply section to fail.
Monitors have AC line filters at
the power input to prevent inter-
ference. A bad cap here would
be right across the AC line. Your
fuse problem could be as simple
as that.
POWER SUPPLIES
POINT AND CLICK MENUS
Select from a list of manufacturers:
Then select the game or topic you want
to view. From there, just point and click
and the issue which contains your
choice will be displayed. Either scroll
through the pages or go directly to the
article of interest.
If your power supply blows fuses,
check your main rectifier(s) and
the voltage regulator. The recti-
fier could be one diode, a bridge
of four discrete diodes, or a
bridge. Whatever it is, it
shouldn't be shorted.
REQUIREMENTS
All that's needed is an IBM compatible
computer (386 or better) with Windows
3.1 (or later) and a CD-ROM player. All
the technical information published in
ST J during the past sixteen years will
be yours in seconds.
Follow the traces from the recti-
fier to the main filter capacitor
and on to the regulator. The big
filters rarely go shorted, they usu-
ally just get leaky or open up.
PRICE
The regulator will be either an IC
regulator (which looks like a tran-
sistor but may have more legs)
or a discrete regulator, which is
to say one made up from indi-
vidual transistors. Anything with
an STR number on it is a regula-
tor IC. Check the regulator IC
for shorts between input and out-
put, and either of those to
ground.
$388. US funds. COD ok in USA. Price
includes shipping US and Canada.
Other countries add $9 via air.
NOTE
Only 100 ST Jon CD-ROM discs were
made by STAR* TECH Journal. The
next run will be in March of 1997 and
will be available first to purchasers of
the initial disc (at half price). Once you
are a registered user of ST J on CD-
ROM you will be offered future CD-
ROM releases at 50% off.
MolNFO
For more information or to order call,
fax, email or otherwise beam your re-
quests to Star Tech Journal. Inc. PO
Box 35, Medford, NJ 08055. Phone:
609/654-5544. Fax: 609/654-1441.
Email: startech@cyberenet.net
With discrete regulators, a
shorted pass transistor usually
shuts down a monitor, but often
does not blow fuses, but check it
anyway. Check the nearby tran-
sistors as well. Your DMM will
lso PROBLEMS
If you just built a conversion and
the monitor gave out when you
powered it up, or if you try to
install a slave monitor, especially
if you don't use a separate isola-
tion transformer for the slave,
and the same thing happens, you
may have isolation problems and
you can almost count on blown
rectifiers and likely some traces
burnt off the PC board. Ground
traces are at risk, and they will
burn out at the narrowest
point(s).
IIMMM ... I'VE SEEN TIIAT BEFORE
My other problem categories re-
quire a more complicated ap-
proach. The best tool you have
takes no space in your tool box.
It is experience. Your experience
can help you. Monitors are all
pretty similar under the skin, so
if something looks familiar, there
is some chance that it is what you
think it is. When troubleshooting
with a schematic, we use it to
identify parts so that we might
locate them in the unit. In th
absence of diagrams, we use
other clues.