Troubleshooting; Introduction; Repair Considerations - Keithley 6517 Service Manual

5.1

Introduction

This section of the manual will assist you in troubleshooting
the Model 6517A. Included are self-tests, troubleshooting
tables, and circuit descriptions. It is left to the discretion of
the repair technician to select the appropriate tests and docu-
mentation needed to troubleshoot the instrument. Note that
disassembly drawings are located at the end of Section 6,
while component layout drawings may be found at the end of
Section 7.
WARNING
The information in this section is
intended for qualified service personnel.
Some of these procedures may expose
you to hazardous voltages. Do not per-
form these hazardous procedures unless
you are qualified to do so.
This section is arranged as follows:
5.2 Repair considerations: Covers some considerations
that should be noted before making any repairs to the
Model 6517A.
5.3 Power-on test: Describes the tests that are performed
on its memory elements each time the instrument is
turned on.
5.4 Front panel tests: Provides the procedures to test the
functionality of the front panel keys and the display.
5.5 Principles of operation: Gives an overview of operat-
ing principles for the analog board, digital board, dis-
play board, and power supply.
5.6 Circuit board checks: Summarizes basic tests for the
various circuit boards to aid in troubleshooting.

Troubleshooting

5.2

Repair considerations

Before making any repairs to the Model 6517A, be sure to
read the following considerations.
CAUTION
The PC boards are built using surface
mount techniques and require special-
ized equipment and skills for repair. If
you are not equipped and/or qualified, it
is strongly recommended that you send
the unit back to the factory for repairs or
limit repairs to the PC board replace-
ment level (see following NOTE). With-
out proper equipment and training, you
could damage a PC board beyond
repair.
NOTE
For units that are out of warranty, com-
pletely assembled PC boards can be
ordered from Keithley to facilitate repairs.
1. Repairs will require various degrees of disassembly.
Disassembly instructions for the Model 6517A are
located in Section 6 of this manual.
2. Do not make repairs to surface mount PC boards unless
equipped and qualified to do so (see previous
CAUTION).
3. When working inside the unit and replacing parts, be
sure to adhere to the handling precautions and cleaning
procedures explained in paragraph 6.2.
4. Many CMOS devices are installed in the Model 6517A.
These static-sensitive devices require special handling
as explained in paragraph 6.3.
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