Motorola PR860 Detailed Service Manual page 54

Maintenance: General Repair Procedures and Techniques
• Chip Components
Use either the RLN-4062 Hot-Air Repair Station or the Motorola 0180381B45 Repair Station for
chip component replacement. When using the 0180381B45 Repair Station, select the TJ-65
mini-thermojet hand piece. On either unit, adjust the temperature control to 700 degrees F.
(370 degrees C), 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 1/8"
(0.3 cm) 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 1/8" (0.3 cm) 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.
• Shields
Removing and replacing shields will be done with the R-1070 station with the temperature control
set to approximately 415°F (215°C) [445°F (230°C) maximum].
To remove the shield:
1. Place the circuit board in the R-1070's holder.
2. Select the proper heat focus head and attach it to the heater chimney.
3. Add solder paste flux around the base of the shield.
4. Position the shield under the heat-focus head.
5. Lower the vacuum tip and attach it to the shield by turning on the vacuum pump.
6. Lower the focus head until it is approximately 1/8" (0.3 cm) above the shield.
7. Turn on the heater and wait until the shield lifts off the circuit board.
8. Once the shield is off, turn off the heat, grab the part with a pair of tweezers, and turn off the
vacuum pump.
9. Remove the circuit board from the R-1070's circuit board holder.
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