Operating instructions
NOTE
Voltages
and
waveforms
given
on
the
diagrams
are
not
absolute
and
may
vary
slightly
between
instruments
.
To
obtain
operating conditions
similar
to
those
used
to
take
these
readings,
see
the voltage
and
waveforms
page
adjacent
to
each
schematic
diagram
.
Note
the
recommended
test
equipment,
front-panel
control
settings,
voltage
and
waveform
conditions,
and
test
equipment
cable
connection
instructions
.
7
.
CHECK
INDIVIDUAL
COMPONENTS
.
The
following
procedures
describe
methods
for
checking
individual
com-
ponents
.
Two-lead
components
that
are soldered
in
place
are
best
checked
by
first
disconnecting
oneend
.
This
iso
lates
the
measurementfrom
the
effects
of
surrounding
circuitry
.
To
avoid
component
damage,
disconnect
the
power
source before
removing
or replacing
semiconductors
.
Transistors
.
The
best
check
of
transistor
operation
is
actual
performance
under
operating
conditions
.
A
transistor
can
be
most
effectively
checked
by
substituting
a
new
com-
ponent
or
one
that has
been
checked
previously
.
However,
be
sure that
circuit
conditions
are
not
such
that a
replace-
ment
transistor
might
also
be
damaged
.
If
substitute
transis-
tors
are
not
available,
use a
dynamic
tester
.
Static-type
testers
are
not
recommended,
since
they
do
not
check
operation
under
simulatedoperating
conditions
.
Integrated
Circuits
.
IC's
can be
checked
with
a voltmeter,
test
oscilloscope,
or
by
direct
substitution
.
A
good
under-
standing
of
circuit
operation
is
desirable
when
trouble-
shooting
circuits
using
IC's
.
Use
care
when
checking
volt-
ages
andwaveforms
around
the
IC's
so that
adjacent
leads
are
not
shorted together
.
A
convenient
means
of
clipping
a
test
probe
to the 14-
and
16-pin
IC's
is
with
an
IC
test clip
.
This device
also
serves
as
an
extraction
tool
.
The
lead
con-
figuration
for the
semiconductors
used
in
this
instrument
are
shown
on
a
pullout
page
in
the
front of
the
diagrams
section
.
Do
not
use
an
ohmmeter
scale
that
has
a
high
internal
current
.
High
currents
may
damage
the
diode
.
Maintenance-71380
Diodes
.
A
diode
can
be
checked
for
an
open
or
shorted
con-
dition
by
measuringthe
resistance
between
terminals
with
an
ohmmeter
scale
having
a
low
internal
source
current,
such
as
the
R
X
1
K
scale
.
The
resistance
should
be
very
high
in
one
direction
and
very
low
when
the
meter
leads
are
reversed
.
The
cathode
end
of
each
glass-encased
diode
is
indicated
by
a
stripe,
a
series
of
stripes,
or a
dot
.
The
cathode
and
anode
ends
of
metal-encased
diodes
are
identified
by
the
diode
symbol
marked
on
the case
.
For
most
silicon
or
germanium
diodes
with
a
series of
stripes,
the
color
code
identifies
the
four
significant
digits
of the
JEDEC
or
vendor
number
using the
resistor
color-code
system
(e .g
.,
a
diode
color-
coded
yellow-brown-green-red
indicates
a
1
N-4152
diode)
.
Resistors
.
Check
resistors
with
an
ohmmeter
.
See the
Re-
placeable
Electrical
Parts
list
for the tolerance of the
resistors
used
in
this
instrument
.
Resistors
normally
do
not
need
to be replaced
unless
the
measured
value
varies
widely
from
that
specified
.
Inductors
.
Check
for
open
inductors
by
checking
conti-
nuity
with
an
ohmmeter
.
Shorted
or
partially
shorted
inductors
can
usually
be
found
by
checking
the
waveform
response
when
high-frequency
signals
are
passed
through
the
circuit
.
Partial
shorting
often
reduces
high-frequency
response
.
Capacitors
.
A
leaky or
shorted
capacitor
can
usually
be
detected
by
checking
resistance
with
an
ohmmeter
on
the
highest
scale
.
Do
not exceed
the voltage
rating
of
the capa-
citor
.
The
resistance
reading
should
be
high
after
initial
charge
of the capacitor
.
An
open
capacitor
can
best
be de-
tected
with
a
capacitance
meter
or
by
checking
that the
capacitor
passes
ac
signals
.
8
.
REPAIR
AND
ADJUSTMENT
.
If
any
defective
parts
are
located,
follow
the
replacement
procedures
given
in
Corrective
Maintenance
.
Be
sure to
check
the
performance
of
any
circuit
that
has
been
repaired
or
hadany
electrical
components
replaced
.