Tektronix 7B10 Instruction Manual page 40

Maintenance— 7B1
0
Diodes
A
diode can be checked
for
an open
or shorted condition
by
measuring
the resistance
between
terminals with an
ohmmeter,
using
a scale
having
a
low
internal source
current,
such
as the
R X IK
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
IN-4152
diode).
Resistors
Check
resistors
with an ohmmeter. See
the Replaceable
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
continuity 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
capacitor.
The
resistance reading should be high
after
initial
charge
of
the
capacitor.
An
open
capacitor can
best
be detected
with
a
capacitance meter
or by
checking
that the
capacitor
does
not pass ac
signals.
8.
REPAIR
AND ADJUSTMENT
If
any
defective parts are
located,
follow the replacement
procedures
in
Corrective
Maintenance. Be
sure
to
check
the
performance
of
any
circuit that
has been
repaired
or
had any
electrical
components
replaced.
CORRECTIVE
MAINTENANCE
Corrective
maintenance
consists of
component
replacement and
instrument
repair.
Special techniques required
to
replace
components
in this
instrument are given
here.
OBTAINING
REPLACEMENT PARTS
All electrical
and mechanical
part
replacements can be
obtained through your Tektronix
Field Office
or
representative.
However,
many
of
the standard
electronic
components
can be
obtained
locally in less
time than
is
required
to
order
them
from
Tektronix,
Inc.
Before
purchasing
or
ordering replacement
parts,
check
the
parts
list
for value, tolerance,
rating,
and
description.
NOTE
When
selecting
replacement
parts,
remember
that the
physical
size
and
shape
of a
component
may
affect
the
performance
of the
instrument,
particularly at
high
frequencies.
AH
parts
should be
direct
replacements
unless a different
component
will
not
adversely
affect
instrument performance.
Some
parts
are
manufactured
or selected by Tektronix,
Inc. to
satisfy particular
requirements,
or are
manufactured
to
specifications
for
Tektronix,
Inc.
Most
of
the
mechanical
parts are
used
in this
instrument have
been manufactured
by Tektronix,
Inc.
To determine
the
manufacturer
of parts, refer to
parts
list.
Cross Index
Mfr.
Code
Number
to
Manufacturer.
When
ordering
replacement
parts
from
Tektronix,
Inc.,
include the following information:
1.
Instrument
type.
2.
Instrument
serial
number.
3.
A
description
of
the
part
(if
electrical,
include
circuit
number).
4.
Tektronix
part
number.
SOLDERING TECHNIQUES
To avoid
electrical
shock, disconnect the
instrument from the
power
source before
soldering.
4-7