Star Tech Journal

_ _ A_u_G_us_T_1_9_a4 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ $TAR*,ECH
MANUFACTS
ATARI SWITCHINCJ POWER SUPPLY
PRECAUTIONS
T
roubleshooting aids are provided
throughout this manual. The following
information is intended to acquaint the service
technician with useful troubleshooting
information.
PRECAUTIONS
Do not troubleshoot the switching power
supply until you are thoroughly familiar with
all precautions described below. Failure to
observe these precautions could result in
serious personal injury or damage to the
power supply.
•
•
NEVER defeat the overcurrent protection
circuit comprised of BR1, U2, and 03. If
this circuit continues to trigger and is
defeated, the power MOSFET 01 and 02
may be destroyed.
When checking the circuitry connected to
the line voltage, ALWAYS use an isolated
oscilloscope.
•
If 01 and 02 fail, replace both transistors
even if one seems to be operating property.
Also, replace R21-R24 even if they seem
to be undamaged.
•
NEVER try to operate only one MOSFET
01 or 02.
•
The 5-volt output must have at least a 1-
ampere load for proper operation. If oper-
ated under no load, the supply will generate
a series of very short pulses.
•
A lightly overloaded condition can cause
the pulse width to be very narrow and may
not set comparator U2 into the latched
condition.
~
VALUE-PACHEO
COMPONENTS.
In just a few years NTE replacement
semiconductors have become the
electronic games industry standard for
quality and value!
And to back up that claim of quality,
we back NTE replacement parts with an
exclusive two-year warranty.
So, next time you need a quality
semiconductor, look for the big green
and white NTE!
QUALITY REPLACEMENT SEMICONDUCTORS
FOR THE ELECTRONIC GAMES INDUSTRY,
INCLUDING THE FOLLOWING
MANUFACTURERS:
• ATARI
• GREMLIN
• BALLY
• MIDWAY
• CINEMATRONICS • STERN
• EXIDY
• WILLIAMS
• GOTTLIEB
Available from your local NTE distributor
CIRCUIT DESCRIPTION
A detailed circuit description of the switching
power supply is provided in Chapter 3 of your
Atari Service Manual TM-238. Refer to this
description to obtain a thorough knowledge
of the operation of the supply circuitry before
attempting to troubleshoot.
NEW-TONE ELECTRONICS, INC.
DEPT. STJ
44 Farrand St. • Bloomfield, NJ 07003
STAR*TECH
JOURNAL
AL'S
AUDIO VIDEO
TECHNICAL
SEMINARS
D
istributor-sponsored S•T J Technical
Seminars are available at no cost to
any distributors interested in assisting their
clients understand operation and mainten-
ance of videos, pins and lasers.
The course is flexible enough to be offered
as a 1 ·, 2-, or 5-day seminar depending upon
your requirements. The course covers Basic
Electronics (electron theory and semicon-
ductors), Video Game Systems (power supplies,
control panel interfaces, rasterscan and X-Y
monitors), Electronic Pinball Systems (elec-
Ironic digital systems), Troubleshooting
Techniques, Test Equipment (digital multi-
meters and logic probes), Proper Soldering
Techniques, Videodisc Operation and Main-
tenance, How to Read Electronic Schematics
and other essential skills.
If you'd like to sponsor an S•T J Technical
Seminar, contact Star•Tech Journal at
609/662-3432 and ask for our information
package. This package helps you plan your
promotion for a successful seminar.
EXPERT SERVICE
ALL PIONEER
LASER DISC PLAYERS
FORMER PIONEER
ENGINEER ON DUTY.
FACTORY
AUTHORIZED
SHIP-IN OR LOCAL
PHONE 201 /342-7634
MOVING? CI.UEBTIONB?
Your address label contains your subscriber
account number in the top right. We can more
readily change your address or answer your
questions if we know this number. If you are
moving and don't have your label, just fill out
the information at right and we'll update your
account.
OLDADDRES ■
NEWADDRE ■■
l
Ycu name _ _ _ _ _ _ _ _ _ _ _ _ _
Ycu name
Company-------------
Company-------------
Address
Ctty/Stata'Zlp _ _ _ _ _ _ _ _ _ _ _ _
Address _ _ _ _ _ _ _ _ _ _ _ _ _
Clty/Stata'Zlp _ _ _ _ _ _ _ _ _ _ _ _
Account#-------------