Disassembly; Introduction; Handling And Cleaning Precautions; Pc-Board Handling - Keithley 2002 Repair Manual

3.1

Introduction

The information in this section explains how to disassemble
the Model 2002. Also discussed are handling and cleaning
considerations as well as the procedure to change the main
CPU firmware in the event of an upgrade. This section is or-
ganized as follows:
3.2 Handling and cleaning precautions: Covers general
precautions to take when troubleshooting inside the
unit, and cleaning procedures when replacing parts.
3.3 Static-sensitive devices: Explains handling proce-
dures for static-sensitive devices.
3.4 Case cover and shield removal: Explains how to re-
move the case cover. Also covered is the removal of
the top shield of the analog board to allow access to
analog circuitry for troubleshooting.
3.5 PC-board removal: Provides the procedures for re-
moving the digital board, A/D converter board and the
analog board.
3.6 Front panel disassembly: Explains how to remove
the display board and/or the front panel switch pad.
3.7 Cooling fan removal: Explains how to remove the
cooling fan from the chassis.
3.8 Firmware replacement: Provides the procedure to
change firmware.
3.9 Instrument re-assembly: Provides some general
guidelines to follow when re-assembling the Model
2002.

Disassembly

3.10 Assembly drawings: Provides mechanical drawings
to assist in the disassembly and re-assembly of the
Model 2002.
3.2

Handling and cleaning precautions

When servicing the instrument, care should be taken not to
indiscriminately touch PC board traces to avoid contaminat-
ing them with body oils or other foreign matter. Mother
board areas covered by the shield have high-impedance de-
vices or sensitive circuitry where contamination could cause
degraded performance.

3.2.1 PC-board handling

Observe the following precautions when handling PC-
boards:
• Wear clean cotton gloves.
• Handle PC-boards only by the edges and shields.
• Do not touch any board traces or components not asso-
ciated with the repair.
• Do not touch areas adjacent to electrical contacts.
• Use dry nitrogen gas to clean dust off PC-boards.

3.2.2 Solder repairs

Observe the following precautions when it is necessary to
use solder on a circuit board:
• Use an OA-based (organic activated) flux, and take care
not to spread the flux to other areas of the circuit board.
3
3-1