Play Meter

Fixing your steering boards
For those of you who still have
doubts about fixing your own
steering boards, this little circuit
may help you get the job done by
letting you know if the infrared light
emitting diode is working or not
(See Technical Topics Update July
1977). The basic circuit is almost
identical to one channel of the
steering board itself with the
inclusion of a visible L.E.D. to
indicate the condition of the output.
CONSTRUCTION
I built my detector on a six pin
edge connector . Since Atari uses
the Molex connector for interface
with the games themselves, using
an edge connector lets you pick off
the five-volt and ground signals to
power the detector, while leaving
the steering board connected to the
game.
The photo-transistor is mounted
on the end of a pair of wires so it can
be placed in front of the L.E.D. in
the steering board. If the L.E.D . is
working, 01 will see the I.R. beam
and start to conduct. This will bias
the amplifier transistor 02 so that it
too begins conducting . The visible
L. E. D. on the output will then be
energized so you can easily see
when the photo-transistor is receiv-
ing a light source.
It's a good idea to mask the
photo-transistor, leaving just a small
hole for the L. E. D. to shine through.
This will keep ambient light in the
room from causing erroneous indi-
cations.
The staff at Play Meter welcomes
any suggestions, comments, tips,
hints, or questions. Address your
letter to:
The Technical Editor
Play Meter Magazine
4136 Washington Avenue
New Orleans, La. 70184
Awakening to solid state
IN Fit#\ fti::P
1.-~~t-tT
3:31 This easy-to-build infrared detector
will tell you if the steering boards
L. E. D. is working or not. The visible
L. E. D. can be any color desired.
Well, it looks like the industry is
finally waking up and getting to
know something about solid state
electronics. As an increasingly
larger percentage of the equipment
goes to digital control, operators
have been forced to get hip to the
repair scene or suffer outrageous
repair bills from local (or not so
local) distributors. Dependency on
outside circuit board or monitor
repair can cause downtime of weeks
or months; so a blown board really
means blown income.
As a result of this equipment
modernization,
smart operators
have been paying big bucks for
technicians to do solid state repair.
This often involves $2,000 or more
in shop equipment, but the invest-
ment is well worth it when you
consider the total cost of the
equipment being operated. There is
however, a missing link in the
business of keeping things running.
When a logic board or monitor fails
on location, can you fix the game
the first time out without having to
return to base for a replacement
board or monitor? Short of carrying
a spare board for every game being
operated, the only logical answer is
in-field printed circuit board repair.
Repairing boards on location is
not only feasible, but highly practi-
cal. If a serviceman has to make two
trips to repair a solid-state machine
(one to diagnose the problem and a
return trip to install a new board),
then there is room for improvement
in present day maintenance and
repair schemes.
Instead of taking your problem to
the technician (with the inevitable
delays involved), why not send your
expert to the problem? Since the
majority of P.C.B. repairs are simple
things like power supply problems
or shorted input buffers (coin
switch, start button, joy sticks,
etc .), fixing a board on location is
often a simple matter of making a
quick diagnosis and replacing the
defective component(5). I've had a
great deal of success doing P.C.B.
repair using only a logic probe, a
V.O.M. and a handful of common
chips.
Hopefully, it won't be long before
the field mechanic becomes a skilled
technician and replacing a bad I.C.
as common a field repair as
changing a burned coil.