Service manual

Repair and
Maintenance
Guidelines
This section provides guidelines for repairing and maintaining the Agilent
E1346A Single Ended Relay Multiplexer including:
• ESD precautions
• Soldering printed circuit boards
• Post-repair safety checks
ESD Precautions Electrostatic discharge (ESD) may damage static sensitive devices in the
multiplexers. This damage can range from slight parameter degradation to
catastrophic failure. When handling multiplexer assemblies, observe the
following guidelines to avoid damaging multiplexer components:
• Always use a static-free work station with a pad of conductive rubber
or similar material when handling multiplexer components.
• If a device requires soldering, be sure the assembly is placed on a
pad of conductive material. Also, be sure that you, the pad, and the
soldering iron tip are grounded to the assembly.
Soldering Printed
Circuit Boards
The etched circuit boards of the multiplexer modules have plated-through
holes that provide a solder path to both sides of the insulating material.
Soldering can be done from either side of the board with equally good
results. When soldering to any circuit board, keep in mind the following
guidelines:
• Avoid unnecessary component unsoldering and soldering. Excessive
replacement can result in damage to the circuit board, adjacent
components, or both.
• Do not use a high power soldering iron on etched circuit boards, as
excessive heat may lift a conductor or damage the board.
• Use a suction device or wooden toothpick to remove solder from
component mounting holes. When using a suction device, be sure
that the equipment is properly grounded.
Post-Repair Safety
Checks
After making repairs to the multiplexer, inspect the multiplexer for any
signs of abnormal internally generated heat, such as discolored printed
circuit boards or components, damaged insulation, or evidence of arcing.
Determine and correct the cause of the condition. Then perform the
functional tests as described in Chapter 2 - Verification Tests to verify that
the multiplexer is functional.
Service 4-7