Tektronix TM 515 User Manual

The associated
plug-ins can be checked for proper

Component
Checking
operation quickly by substituting other like units known to

If a
component cannot be disconnected from its circuit,
be operating properly
. Ifthetroublepersistsaftersubstitu-

then the effects of the associated
circuitry must be
lion, then the power module is probably at fault . Moving a
properly operating plug-infrom oneappropriate compart-

considered when evaluating
the measurement . Exceptfor
ment to another might help determine if one or more

soldered-in
transistors and integrated circuits, mostcom-
compartments
have
a
problem .

ponents can be lifted at one end from the
circuit board .
Visual Check
Inspect the portion of the system in whichthetroubleis
suspected . Many troubles can be located by visual clues
such as unsoldered connections, broken wires, damaged
circuit boards, damaged components, etc .
Note the trouble symptoms . These often identify the
circuit in which the trouble is located .
When trouble
symptoms
appear in more than one circuit, check the
affected circuits by making waveform and voltage
measurements .
Incorrect operation of all circuits often means
trouble
in the power supplies .
Using
a
multimeter, check first for
correct voltages of
the individual regulated supplies
according to
the plug-in schematics and calibration
procedures . Defective components elsewhere
in the irr
struments can appear as
power supply problems . I n these
instances, suspected circuits should be disconnected
from apparently bad power supplies one at
a time to
narrow the search
.
Voltages and Wavefams
Transistors and IC's
Turn the POWER switch OFF before removing or
replacing any semiconductor .
A good check of transistor
operation is actual pertor-
mance under
operating conditions . A transistor can most
Instrument Calibration

effectively be
checked by substituting a new component
for it (or one which has been checked
previously) .
Check the calibration of the suspected plug-in or the

However,besurethatcircuitconditionsarenotsuchthata
affected circuit if the trouble is obviously in a certain

replacement transistor might also be damaged .
circuit . The trouble may only bea result of misadjustment
or may be corrected by re-calibration . Complete
calibra-
tion instructions are given in the manual for each instru-

If
substitute
transistors are not available, usea dynamic
ment in the system .

tester . Static-type testers are not recommended, since
they do not check
operation under simulated operating
conditions . A suction-type desoldering tool must be used
to remove soldered-in transistors ; see
Component
Circuit Isolation

Replacement procedure for details .
Integrated circuits
can
be checked
with a voltmeter,
test oscilloscope, or
by direct substitution . A good
understanding of the circuit description is essential to
troubleshooting circuits using IC's . Operatingwaveforms,
logic levels, and other operating information for the
IC's
are given in the
Circuit Description section of the ap-
propriate manual . Use care when checking voltages and
waveforms 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 in-line
IC's
is with an
integrated circuit test clip . This device also doubles as an
extraction tool .
Diodes
Maintenance-TM 515
Do
not use an ohmmeter that has a high internal
current . High currents maydamage the diode .
Often, defective components can be located by
using
waveform and voltage indications when
they appear on
the schematic or in the calibration
procedures . Such

A diode
may be checked for an open or shorted
waveforms and
voltage labels are typical indications and

condition by measuring the resistance betweenterminals .
will vary between instruments . To obtain operating con-

When an ohmmeter scale having an internal source of
ditions similar to those used to take these readings,
refer

between 800 mV and 3 V, the resistance should be
very
to the first diagram in the service section of
the plug-in

high in one
direction and very low when the leads are
manuals .

reversed .

Tektronix TM 515 Specifications

General

Brand	Tektronix
Model	TM 515
Category	Power Supply
Language	English