Motorola ASTRO XTSTM 4000 Detailed Service Manual page 20

1-4
1.3.2 Chip Components
Use the RLN4062 Hot-Air Repair Station for chip component replacement. Adjust the temperature
control to 390 °C (735 °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.
NOTE Parts U1401 and U1304 are not field repairable. For failures relating to U1401 and
U1304, the mainboard has to be replaced.
May 28, 2008
Introduction: General Repair Procedures and Techniques
6871620L01-C