Atari Breakout - Test Equipment; Basic Test Equipment

nents
were
installed
correctly.
If
this
was
done
properly,
then
start
the
troubleshooting
steps
over
again.
Keep
in
mind
that
there
may
be
more
than
one
trouble
at a
time,
and
that
correcting
one
trou-
ble
can
sometimes
bring
previously
undetectable
troubles
to
light.
This
verification
is
especially
important
when
the
original
trouble
had
been
intermittent,
that
is,
was
not
happening
all
the
time.
6.2
TEST
EQUIPMENT
Electronic
troubleshooting
of
a
video
game es-
sentially consists
of
checking
for
the
presence
of
var-
ious
signals
and
of
examining
their
condition.
A sig-
nal
can
be
thought
of
as
acting
like
a
"messenger"
that
carries
instructions
from
one
unit
or
circuit
to
another.
Many
different
types
of
signals
are
pro-
duced
in
a
video
game,
and
for
this
reason
several
unusual
and perhaps
unfamiliar
types
of
test
instru-
ments
are
used
during
troubleshooting.
Each
in-
strument
has
its
own
set
of
advantages
and
disad-
vantages
for
examining
a
given
type
of
signal,
and
both
the
depth
of
the
intended
troubleshooting
capability
and
budget
will
determine
what
instru-
ments
will
be
needed.
Some
instruments
are basic
and
essential,
no
matter
what
size
of
service
facility,
while
other
optional
instruments
are
desirable
be-
cause
they
make
troubleshooting
easier
and
quicker.
6.2.1
BASIC
TEST
EQUIPMENT:
(a)
The Video Probe.
This is a
simple
but
invalu-
able
instrument
having
two
leads-a
test-clip
lead
and
a
test-probe
lead.
During
troubleshooting
of
video
signals
the
test-clip
lead is
left
connected
to
the
game side
of
the
video
coupling
capacitor.
On
the
Breakout
game
this
point
is
the
junction
of
resis-
tors
R41,
R42, R43,
R51
and
R52
on
the
PCB.
When
the
test-probe
lead
is
then
connected
to
any
video
developmental
signal,
that
signal
will
be
coupled
to
the
video
signal
going
to
the
TV
monitor
and a
video
probe
picture
will
appear
on
the
TV
screen.
The
shape
and
other
characteristics
of
this
picture
will
give
information
about
the
signal
being
probed.
The
video
probe
is
suited
for
troubleshooting
syn-
chronization
and image
signals,
but
will
not
be use-
ful
for
extremely
fast
signals
(such
as
the
clock)
or
for
very
slow
analog
or
digital
signals.
A
video
probe
can be
constructed
in a
few
min-
utes
from
these
common
electrical
components:
a
length
of
20
AWG
(American
Wire
Gauge)
rubber-
coated
wire,
a
4.7K-ohm,
%-watt
carbon
resistor,
and
two
test
leads.
For
the
leads,
use
a
single
Mouser
test
clip
(Mouser#
131
C301
or
302)
attached
to
one
end
of
the
wire,
and
a
test
prod
containing
the
resistor
on
the
other.
To
assemble
the
video
probe,
proceed
as
fol-
lows:
Remove
the
cap
from
the
test
clip
and
strip
3/16
inch
off
each
end
of
the
wire.
Solder
one
end
to
the
post
in
the
test
clip,
thread
the
other
end
through
the
hole
in
the
cap,
and
snap
on
the
cap.
Next
unscrew
the
plastic
body
of
the
test
prod
from
the
point
and
trim
both
leads
of
the
resistor
to
a
3/16-inch
length.
Solder
one
resistor
lead
to
the
in-
side
of
the
point.
Thread
the
other
end
of
the
wire
through
the
hole
in
the
body
and
solder
it
to
the
other
resistor
lead;
screw
the
body
back
onto
the
point.
(b) The
Logic
Probe.
This
is a
test
instrument
designed
for
fast
verification
of
digital
IC
outputs.
It
is
small,
convenient
to
carry, easy
to
read, and
rela-
tively
inexpensive. The
logic
probe
derives its
power
from
the
system
under
test;
it
has
two
power
leads,
one
for
connection
to
ground
and
the
other
to+
5
volts DC.
When
the
logic
probe's
tip
is
held
against a
digital
signal
point,
three
colored
lamps
in
the
tip
will
indicate
the
signal's
condition
or
state,
as
fol-
lows:
•
The
red
lamp
lit
indicates
a
high
or
logic
level
1
(for
TIL
components,
this
is
+ 2.4
to
+ 5
volts)
•
The
white
lamp
lit
indicates
a
low
or
logic
level
0
(for
TIL
components,
this
is
0
to
+0.8
volt)
•
The
blue
lamp
lit
indicates
that
the
signal
is
changing
states
•
No
lamps
lit
indicate
the
grey
region
between
0
and 1
(for
TIL
this
is
between+
0.8
and+
2.4
volts)
A
circuit
shorted
to
ground
will
illuminate
the
white
lamp
and
an
open
circuit
will
illuminate
the
red
lamp.
The
logic
probe
is
readily
available
from
elec-
tronic
supply
sources;
a
commercial
model
found
satisfactory is
the
Kurz-Kasch
model
.
LP
520.
(c)
The Logic Pulser.
This test
instrument
is
simi-
lar
in
size
and
shape
to
the
logic
probe,
and
it
also
derives its
power
from
the
system
under
test.
When
the
logic
pulser's
tip
is
held
against
a
digital
signal
point,
the
source
and
sink
capabilities
of
the
pulser
override
any
IC
output
and
the
point
is
driven
to
the
opposite
logic
level.
If
the
point
that
the
logic
pulser
is
held
against
is
low,
pressing
the
switch
on
the
side
of
the
pulser
will
introduce
a
high
pulse.
Con-
versely,
pulsing
a
high
line
will
pull
that
line
low
momentarily.
During
troubleshooting
the
logic
pulser
allows
stimulation
of
in-circuit
ICs
with
a
shaped
digital
pulse.
For
example,
a
certain
feature
of
the
game
may
not
be
working
and
you
suspect
that
a
circuit
is
not
receiving
the
necessary
signal. Use
the
pulser
to
imitate
that
signal:
if
the
circuit
begins
working,
you
have
proved
that
the
signal
was
in
fact
missing
and
you
can
begin
tracking
it
down.
This
technique
is
very
similar
to
jumping
coils
in
electromechanical
games such
as
pinball
machines.