TECHNICAL TIP
TBOUBLESHOOTING PINBALL
SWITCH DECODEBS
Problems associated with switches
and switch common sometimes in-
volve checking the decoders. These
74145 decoders are open collector
devices and are easily checked with the
built-in self-test system or a video
probe and a logic probe.
1. A portion of the built-in self-test
program in Atari pinball games will
perform a switch test. An indicator
on the game display will identify
which switch is closed. If the self-
test program is not operating
properly, use the following pro-
cedure.
2. Connect the video probe to switch
common chip C9 Pin 13. Clip the
other end of the video probe to the
test probe on the logic probe.
3. Disconnect edge connector J7 from
the PCB. Turn off all option
switches on main logic PCB. Turn
the score replay level to "O". Insure
switch common is high with no
pulses.
4. Check each 74145 decoder. All out-
puts being used should be high
pulsing. low. If not, replace the
corresponding 74145.
5. Also, chip Ell, a "9301" decoder,
commonly fails when switch com-
mon blows up. As a one-of-ten
decoder, only one output pin can be
low at a time. Check each out-
put pin.
6. The ROM/RAM tester can be used to
check each decoder. The memory
address of each 74145 output is
printed in every Atari pinball
manual next to the corresponding
edge connector output pin. With the
aid of this tester a simple logic
probe can be used to accurately
trace logic problems to component
level. Problems involving switches
turning on the wrong thing are
easily found using the ROM/RAM
tester.
INDY RETROFIT
KIT OFFERED
Atari is offering a power supply
retrofit kit at no charge for all INDY
800™ and INDY 4™ games in the field.
This kit is designed to improve the
performance, decrease operating
temperatures and increase reliability
of the power supply on these games.
The kit comes complete with detailed
instructions for installation and all
parts needed.
To obtain the free INDY power
supply kit call Atari Customer Service
at (800) 538-1611 (West) or (800)
631-5374 (East). Ask the customer
service representative for kit No.
A, 034483-01. Please specify the serial
numbers on the INDY 800 or INDY 4
games you have when requesting the
kit.
K \ l\
- s- ~ d--.
THE CLASSICS ARE BACK
There are a few select games in this
industry that can truly be called
classics. Atari's drivi,g} games,
SPRINT 2™, SUPERBUG , and SIT
DOWN NIGHT DRIVER™ uniquely fall
into this category of truly classic
games that consistently earn. Each of
these games has characteristics that
draw enthusiastic driving game
players again and again.
SUPERBUG, with its bright yellow
Volkswagen racing through city
streets, truly has appeal for all ages.
The unpredictable winding course and
realistic engine sounds and crashes
make this game one the players will
always enjoy.
The nighttime racing thrills of SIT
DOWN NIGHT DRIVER will always be
a prime attraction. Having exceptional
features and collection records marks
this as the top sit-down driving
game yet.
SPRINT 2 undoubtedly fits into the
classic category. It is a two-player
driving phenomenon that offers more
variation and challenges than any
other. The high collections over the
past years in almost any type of loca-
tion has certainly been responsible for
the reputation of SPRINT 2.
It is a fact that driving games are
consistently among the top games in
any game room location. Atari has
always been the leader in new driving
game innovations. Among the best
over the years certainly would be
named SPRINT 2, SIT DOWN NIGHT
DRIVER and SUPERBUG. ''We still
have many requests for these games. It
seems that there are very few on the
used game market; therefore, Atari
has decided to make a limited quantity
of these games available again through
Atari distributors," reported Frank
Ballouz, National Sales Manager.
SERVICE SCHOOLS
SCHEDULED
Service Schools covering all technical
aspects of both video and pinball will
be held by Atari's Field Service Staff at
the following locations:
April 19 & 20 - Mountain Coin, Denver
April 23 & 24 - Rowe International,
Phoenix
.
May 7 & 8 - New Way Sales, Toronto
May 10 & 11 - Coin Machine Dist.
Peekskill, N. y.
May 14 & 15 - Philip Moss, Des Moines
May 17 & 18 - Philip Moss, Kansas City
May 21 & 22 - Philip Moss, Omaha
Please contact the distributor for
reservations or information.