Motorola CP 140, Detailed Service Manual

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2-4 MAINTENANCE
Shields
Removing and replacing shields will be done with the R1070 station with the temperature control
set to approximately 215
°
C (415
°
F) [230
°
C (445
°
F) maximum].
■ To remove the shield
:
1.
Place the circuit board in the R1070 circuit board 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 0.3 cm (1/8”) 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 R1070 circuit board holder.
■ To replace the shield:
1.
Add solder to the shield if necessary, using a micro-tipped soldering iron.
2.
Next, rub the soldering iron tip along the edge of the shield to smooth out any excess
solder. Use solder wick and a soldering iron to remove excess solder from the solder
pads on the circuit board.
3.
Place the circuit board back in the R1070 circuit board holder.
4.
Place the shield on the circuit board using a pair of tweezers.
5.
Position the heat-focus head over the shield and lower it to approximately 0.3 cm (1/8”)
above the shield.
6.
Turn on the heater and wait for the solder to reflow.
7.
Once complete, turn off the heat, raise the heat-focus head and wait approximately one
minute for the part to cool.
8.
Remove the circuit board and inspect the repair. No cleaning should be necessary.