4-6
Document number: S46-901-01 Rev. F / March 2011
Section 4: Service Information
S46/S46T/S46L Microwave Switch System Instruction Manual
Mainframe replacement parts
Replacement parts for the mainframe can be obtained directly from Keithley Instruments. See the
Keithley Instruments website (
www.keithley.com
) for specific part numbers.
WARNING
Use only the parts specified on the Keithley Instruments website
(
www.keithley.com
)
when servicing the equipment. Use of improper parts
may expose the operator to hazardous voltages that could result in
personal injury or death. Do not attempt to replace parts or otherwise
service the equipment unless you are qualified to do so.
Replacement precautions
CAUTION
Observe the following precautions when replacing components:
• To avoid contamination which could degrade switch performance, always
handle the switch only by the covers and side edges. Do not touch the
connector, board surfaces, or components on the switch.
• Use care when removing components from the PC board to avoid pulling
traces away from the circuit board. Before attempting to remove a relay,
use an appropriate desoldering tool to clear each mounting hole
completely free of solder.
Soldering considerations
When using solder on the circuit board, observe the following precautions:
•
Use SAC Tin/Silver/Copper on lead free PC boards which are identified with a "Lead Free"
label. Use Tin/Lead solder on non-lead free boards.
•
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, 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.
Disassembly
To disassemble the S46/S46T/S46L in order to gain access to and replace the relays or other
components, perform the following steps (refer to
and
):
WARNING
Before disassembly, disconnect all power sources and remove the
instrument from the instrument rack.
1.
Disconnect all power sources and remove the S46 from the instrument rack.
2.
Remove the screws that secure the top cover.
