Tektronix ECO 422, Instruction Manual

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Maintenance
7–4
ECO 422
Instrument performance should be checked after each 2000 hours of operation, or
every 12 months. This will help to ensure maximum performance and assist in
locating defects that may not be apparent during regular operation. The
Performance Verification and Adjustment Procedures are included in this
manual.
Corrective Maintenance
The following procedure is designed to assist in isolating problems, which in
turn expedites repairs and minimizes down time. There are no specific trouble-
shooting procedures for this instrument because it is a very simple instrument.
NOTE
. There are two fuses in this instrument. One is accessible through the rear
panel and the other is on the power supply. Make sure to check the internal fuse
if the instrument will not power up.
Ensure that the malfunction exists in the instrument. This is done by making sure
that the instrument is operating as intended by Tektronix (see Operating Basics),
and by checking that a malfunction has not occurred upstream from the
ECO 422.
Determine and evaluate all trouble symptoms. This is accomplished by isolating
the problem to a general area, such as an assembly. The block diagram, given
with the schematics or the Theory of Operation, is a valuable aid in signal
tracing and circuit isolation.
CAUTION.
Use extreme care when probing with meter leads or probes. The
components are very dense and there is only limited access within the instru-
ment. The inadvertent movement of leads or a probe could cause a short circuit
or transient voltages capable of destroying components.
Determine the nature of the problem. Attempt to make the determination of
whether the instrument is out of calibration or if there has been a component
failure. Once the type of failure has been determined, proceed on to identify the
functional area most likely at fault.
Visually inspect the suspect assembly for obvious defects. Most commonly these
will be broken or loose components, improperly seated components, overheated
or burned components, chafed insulation, etc. Repair or replace all obvious
defects. In the case of overheated components, determine the cause of overheat-
ing and correct the cause before re-applying power.
Performance Verification
and Readjustments
General Troubleshooting
Procedures