Keithley 7077, Инструкция по эксплуатации

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4
Service Information
4-1
4.1 Introduction
This section contains information on servicing the Model
7077.
WARNING
The matrix configuration procedures
and installation in this section should
only be performed by qualified person-
nel who recognize shock hazards and
are familiar with the safety precautions
required to avoid possible injury. Re-
view the safety precautions found at the
front panel this manual.
4.2 Handling and cleaning precautions
Because of the high impedance circuits on the Model 7077,
care should be taken when handling or servicing the card to
prevent possible contamination, which could degrade perfor-
mance. The following precautions should be taken when
handling the matrix card.
• Do not store or operate the card in an environment
where dust could settle on the circuit board. Use dry ni-
trogen gas to clean dust off of the card if necessary.
• Handle the card only by the handle and side edges. Do
not touch any board surfaces, components, or edge con-
nectors. Do not touch areas adjacent to electrical con-
tacts. When servicing the card, wear clean cotton
gloves.
• If making solder repairs on the circuit board, use a flux
that is rosin RMA based. Remove the flux from these
areas when the repair is complete using Genesolve or
the equivalent and clean cotton swabs. Take care not to
spread the flux to other areas of the circuit board. Once
the flux has been removed, swab only the repaired area
with methanol, and then blow-dry the board with dry ni-
trogen gas.
• To avoid dirt build-up, operate the switching matrix and
matrix card in a clean environment. If the card becomes
contaminated, it should be thoroughly cleaned.
• After cleaning, the card should be placed in a 50
°
C low
humidity environment for several hours.
CAUTION
Do not store the card by leaning it
against an object (such as a wall) with its
edge connectors in contact with a con-
taminated surface (such as the floor).
The edge connectors will become con-
taminated, and tapes and solder connec-
tions on the pc board may break as the
card bends. ALWAYS store the card (in
its anti-static bag) in the original ship-
ping carton.
4.3 Card installation and removal
WARNING
To avoid electrical shock that could re-
sult in injury or death, ALWAYS remove
power from the entire system (Model
707 or 708, test instruments, DUT, etc.)
and make sure stored energy in external
circuitry is discharged before perform-
ing any of the following: