HP E1328A, Руководство по обслуживанию, Страница: 53 / 70

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After you remove a MOS or CMOS device from an assembly, place
the device onto a pad of conductive foam or other suitable holding
material.
•
If a device requires soldering, be sure the assembly is placed on a
pad of conductive material. Also, be sure you, the pad, and the
soldering iron tip are grounded to the assembly. Apply as little heat
as possible when soldering.
•
When you replace a MOS or CMOS device, ground the foam to the
DAC before removing the device from the foam.
Soldering Printed
Circuit Boards
The etched circuit boards in the DAC have plated-through holes that allow 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.
CAUTION
Do not use a sharp metal object such as an awl or twist drill, since
sharp objects may damage the plated-through conductor.
•
Avoid unnecessary component unsoldering and soldering.
Excessive replacement can result in damage to the circuit board
and/or adjacent components.
•
Do not use a high power soldering iron on etched circuit boards
(a 38-watt soldering iron is recommended), 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
the equipment is properly grounded to prevent electrostatic
discharge from damaging CMOS devices.
Post-Repair Safety
Checks
After making repairs to the HP E1328A DAC, inspect the DAC 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 run the self-test
(*TST? command) to verify that the DAC is functional.
Chapter 8 Service 53