Maintenance-2225 Service
TROUBLESHOOTING TECHNIQUES
The following procedure is arranged in an order that
enables checking simple trouble possibilities before
requiring more extensive troubleshooting. The first
four steps ensure proper control settings,
connections, operation, and adjustment. If the
trouble is not located by these checks, the
remaining steps will aid in locating the defective
component. When the defective component is
located, replace it using the appropriate replace-
ment procedure given under Corrective Mainte-
nance in this section.
Before using any test equipment to make
measurements on static-sensitive,
current-
sensitive, or voltage-sensitive components or
assemblies, ensure that any voltage or
current supplied by the test equipment does
not exceed the limits of the component to be
tested.
1.
Check Control Settings
Incorrect control settings can give a false indication
of instrument malfunction. If there is any question
about the correct function or operation of any
control, refer to either the Operating Information in
Section
2
of this manual or to the Operators Manual.
3.
Visual Check
Perform a visual inspection. This check may reveal
broken connections or wires, damaged com-
ponents, semiconductors not firmly mounted,
damaged circuit boards, or other clues to the cause
of an instrument malfunction.
I
WARNING
(
Dangerous potentials exist at several points
throughout this instrument. If it is operated
with the cabinet removed, do not touch
exposed connections or components.
4.
Check Instrument Performance and Adjustment
Check the performance of either those circuits
where trouble appears to exist or the entire instru-
ment. The apparent trouble may be the result of
misadjustment. Complete performance check and
adjustment instructions are given in Sections
4
and
5
of this manual.
5.
Isolate Trouble to a Circuit.
To isolate problems to a particular area, use any
symptoms noticed to help locate the trouble. Refer
to the troubleshooting charts in the Diagrams
section as an aid in locating a faulty circuit.
6.
Check Power Supplies.
2.
Check Associated Equipment
Before proceeding, ensure that any equipment used
with the instrument is operating correctly. Verify that
input signals are properly connected and that the
interconnecting cables are not defective. Check that
the ac-power-source voltage to all equipment is
correct.
WARNING
)
For safety reasons, an isolation transformer
must be connected whenever troubleshooting
is done
in
the Preregulator and Inverter Power
Supply sections of the instrument.
I
WARNING
)
To avoid electrical shock, disconnect the
instrument from the ac power source before
making a visual inspection of the internal
circuitry.
When trouble symptoms appear in more that one
circuit, first check the power supplies; then check
the affected circuits by taking voltage and waveform
readings. Check first for the correct output voltage
of each individual supply. These voltages are
measured between the power supply test points and
ground (see the associated circuit board illustration
and Table
6-5).
Scam
by
ARmK
MEDU
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