Keithley 7001, Инструкция по эксплуатации

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Maintenance
7-2
the factory. The backplane, micro DIN,
BNC, and power supply boards use
conventional assembly techniques
and can be repaired at the component
level, but board replacement is still
recommended.
Without proper tools or training, you may in ß ict fur-
ther damage which cannot be repaired at the factory.
Such damages may void the warranty.
7.3 Handling and cleaning
7.3.1 Backplane board
Row signal paths for Model 701X series switching
cards are extended onto the backplane boards of the
mainframe. Thus, a contaminated backplane will de-
grade card isolation speci
Þ cations. If an isolation prob-
lem is due to a contaminated backplane, then the
backplane board will have to be removed and cleaned.
Paragraph 7.5.2 explains how to remove the backplane
board.
Handling backplane board
Observe the following precautions when handling the
backplane board:
• Handle the board only by the edges.
• When servicing the board, wear clean cotton
gloves.
• Do not touch any board traces or components not
associated with the repair.
• Do not touch areas adjacent to electrical contacts.
• Use dry nitrogen gas to clean dust off the board.
Solder repairs and cleaning
• Use an OA-based (organic activated) ß ux, and take
care not to spread the ß ux to other areas of the
board.
• Remove the ß ux from the work areas when the re-
pair has been completed. Use pure water along
with clean foam-tipped swabs or a clean soft brush
to remove the
ß ux.
• Once the ß ux has been removed, swab the repaired
area (or contaminated area) with methanol, then
blow dry the board with dry nitrogen gas.
• After cleaning, the board should be allowed to dry
in a 50°C low-humidity environment for several
hours.
7.3.2 Static-sensitive devices
CMOS devices are designed to operate at high imped-
ance levels for lower power consumption. As a result,
any static charge that builds up on your person or
clothing may be suf
Þ cient to destroy these devices if
they are not handled properly. Use the precautions be-
low when handling static-sensitive devices:
CAUTION
Many CMOS devices are installed in
the Model 7001. Generally, all ICs
and transistors should be handled as
static-sensitive devices.
1. Transport such devices only in containers de-
signed to prevent static build- up. Typically, these
parts will be received in anti-static containers of
plastic or foam. Always leave the devices in ques-
tion in their original containers until ready for in-
stallation.
2. Remove the devices from their protective contain-
ers only at a properly grounded work station. Also,
ground yourself with a suitable wrist strap.
3. Handle the devices only by the body; do not touch
the pins or terminals.
4. Any printed circuit board into which the device is
to be inserted must also be properly grounded to
the bench or table.
5. Use only anti-static type de-soldering tools.
6. Use only soldering irons with properly grounded
tips.
7. Once the device is installed on the PC board, it is
usually adequately protected, and normal han-
dling can resume.
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