Appendix B Limited Level 3 Servicing
B.1 Maintenance
For details on the following, please refer to “Chapter 5 Disassembly/Reassembly Procedures” on
page 5-1 to section 5.4 on page 5-4.
Section 5.2 on page 5-1 to Section 5.4 on page 5-4.
• Preventive maintenance (inspection and cleaning).
• Safe handling of CMOS and LDMOS devices.
• Repair procedures and techniques.
B.2 Chip Components
Use a Hot-Air Repair Station for chip component replacement. Adjust the temperature control to
370°C (700°F), and adjust the airflow to a minimum setting. Airflow can vary due to component
density.
• To remove a chip component:
1. Use a hot-air hand piece and position the nozzle of the hand piece approximately 0.3 cm
(1/8") above the component to be removed.
2. Begin applying the hot air. Once the solder reflows, remove the component using a pair
of tweezers.
3. Using a solder wick and a soldering iron or a power desoldering station, remove the
excess solder from the pads.
• To replace a chip component using a soldering iron:
1. Select the appropriate micro-tipped soldering iron and apply fresh solder to one of the
solder pads.
2. Using a pair of tweezers, position the new chip component in place while heating the
fresh solder.
3. Once solder wicks onto the new component, remove the heat from the solder.
4. Heat the remaining pad with the soldering iron and apply solder until it wicks to the
component. If necessary, touch up the first side. All solder joints should be smooth and
shiny.
• To replace a chip component using hot air:
1. Use the hot-air hand piece and reflow the solder on the solder pads to smooth it.
2. Apply a drop of solder paste flux to each pad.
3. Using a pair of tweezers, position the new component in place.
4. Position the hot-air hand piece approximately 0.3 cm (1/8") above the component and
begin applying heat.
5. Once the solder wicks to the component, remove the heat and inspect the repair. All
joints should be smooth and shiny.
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