Keithley 7017, Instruction Manual

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4
Servicing
4-1
4.1 Introduction
This section contains information necessary to service the
Model 7017 and includes information on handling and clean-
ing, performance verification, as well as principles of opera-
tion and troubleshooting.
WARNING
The information in this section is intended
for qualified service personnel only. Some
of the procedures may expose you to haz-
ardous voltages that could result in per-
sonal injury or death. Do not perform
these procedures unless you are qualified
to do so.
4.2 Handling and cleaning precautions
Because of the high-impedance areas on the Model 7017,
care should be taken when handling or servicing the card to
prevent possible contamination. The following precautions
should be observed when servicing the card.
4.2.1 Handling precautions
Observe the following precautions when handling the multi-
plexer card:
• Handle the card only by the edges and shields.
• Do not touch connector insulators.
• Do not touch any board surfaces or components not as-
sociated with the repair.
• Do not touch areas adjacent to electrical contacts.
• When servicing the card, wear clean cotton gloves.
• Do not store or operate the card in an environment
where dust could settle on the circuit board.
• Use dry nitrogen gas to clean dust off of the board if
necessary.
4.2.2 Soldering considerations
Should it become necessary to use solder on the circuit
board, observe the following precautions:
• Use an OA-based (organic activated) flux, and take care
not to spread the flux to other areas of the circuit board.
• Remove the flux from the work areas when the repair
has been completed. Use pure water along with clean
cotton swabs or a clean soft brush to remove the flux.
• Once the flux has been removed, swab only the repaired
area with methanol, and then blow-dry the board with
dry nitrogen gas.
• After cleaning, allow the card to dry in a 50
°
C low-
humidity environment for several hours before use.
4.3 Performance verification
The following paragraphs provide performance verification
procedures for the Model 7017. These tests include insertion
loss and isolation tests.