Keithley 2701, Service Manual

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4-2 Troubleshooting Model 2701 Service Manual
Introduction
This section of the manual will assist you in troubleshooting and repairing the Model 2701.
Included are self-tests, test procedures, troubleshooting tables, and circuit descriptions. It is left
to the discretion of the repair technician to select the appropriate tests and documentation
needed to troubleshoot the instrument. Refer to the disassembly procedures in
Section 5 and
the parts lists in Section 6 for further information.
WARNING The information in this section is intended only for qualified service per-
sonnel. Do not perform these procedures unless you are qualified to do so.
Some of these procedures may expose you to hazardous voltages that could
cause personal injury or death. Use caution when working with hazardous
voltages.
Repair considerations
Before making any repairs to the Model 2701, be sure to read the following considerations.
CAUTION The PC boards are built using surface mount techniques and require
specialized 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 replacement level.
Without proper equipment and training, you could damage a PC board
beyond repair.
• Repairs will require various degrees of disassembly. However, it is recommended that
the Front Panel Tests be performed prior to any disassembly. The disassembly instruc-
tions for the Model 2701 are contained in
Section 5 of this manual.
• Do not make repairs to surface mount PC boards unless equipped and qualified to do so
(see previous CAUTION).
• When working inside the unit and replacing parts, be sure to adhere to the handling pre-
cautions and cleaning procedures explained in
Section 5 .
• Many CMOS devices are installed in the Model 2701. These static-sensitive devices
require special handling as explained in
Section 5 .
• Whenever a circuit board is removed or a component is replaced, the Model 2701 must
be recalibrated. See
Section 2 for details on calibrating the unit.