Motorola HT 1000 service manual Removing and Replacing, Shields

	Once the part is off, turn off the heat, grab the part with a pair of
	tweezers, and turn off the vacuum pump. Prepare the circuit board for
	the new component by applying solder paste flux to the solder pads.
	Position the circuit board under the heat-focus head, lower the head
	to approximately 1/8”-1/4” (0.3cm-0.6cm) above the board, and turn
	on the heat. When the solder left behind on the pads reflows, turn off
	the heat and raise the heat-focus head. Remove the circuit board from
	the holder and inspect the pads to ensure that the solder has flattened
	out and that there are no solder shorts. Clean the area with alcohol
	and a small brush.
	Once the preparation is complete, place the circuit board back in the
	circuit board holder. Add solder paste flux to the solder pads and place
	the new component on the circuit board. Position the heat-focus head
	over the component and lower it to approximately 1/8”-1/4” (0.3cm-
	0.6cm) above the carrier. Turn on the heater and wait for the
	component to reflow.
	Once the component reflows, raise the heat-focus head and wait
	approximately one minute for the part to cool. Remove the circuit
	board and inspect the repair. No cleaning should be necessary.
Shields
Removing and Replacing the	will be done with the R-1319, using the same procedure used to
Shields:	remove and replace TSOP and PBGA components.
	Place the circuit board in the circuit board holder. Select the proper
	heat focus head and attach it to the heater chimney. Add solder paste
	flux around the base of the shield. Position the shield under the heat-
	focus head. Lower the vacuum tip and attach it to the shield by
	turning on the vacuum pump. Lower the focus head until it is
	approximately 1/8”-1/4” (0.3cm-0.6cm) above the shield. Turn on the
	heater and wait until the shield lifts off the circuit board. Once the
	shield is off, turn off the heat, grab the part with a pair of tweezers, and
	turn off the vacuum pump. Remove the circuit board from the circuit
	board holder.
	To replace the shield, add solder to the shield if necessary, using a
	micro-tipped soldering iron. 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. Place the circuit board back in the circuit board holder.
	Place the shield on the circuit board using a pair of tweezers. Position
	the heat-focus head over the shield and lower it to approximately 1/
	8”-1/4” (0.3cm-0.6cm) above the shield. Turn on the heater and wait
	for the solder to reflow.
	Once complete, turn off the heat, raise the heat-focus head, and wait
	approximately one minute for the part to cool. Remove the circuit
	board and inspect the repair. No cleaning should be necessary.
RF PA (U105)	The procedure for removing and replacing the RF PA is very similar to
	the procedure for removing and replacing an PBGA or a TSOP
	component. But because the device is large, extra heating time is
	required to flow the pads. And as a result, neighboring components
	(especially those on the opposite side of the circuit board) will heat,

48