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To Remove the RF PA,
To Replace the RF PA;
reflow, and may inadvertently move. Be careful when performing the
following procedure.
Refer to Figure 17 for RF PA nomenclature.
Figure 17 RF PA Nomenclature
add flux to the leads of the device, and use a soldering iron and pair of
tweezers to heat and lift each lead free and clear of its respective solder
pad on the circuit board. Use the R-1319 Rework Station and the heat-
focus head designed especially for removal of the RF PA. Attach the
heat-focus head to the chimney heater. Adjust the temperature control
to approximately 415 degrees F (215 degrees C) 445 degrees F (230
degrees C) maximum. Apply solder paste to the exposed solder pads
under the PA. Place the circuit board in the circuit board holder, and
position the RF PA under the heat-focus head. Lower the heat-focus
head until it is approximately 1/8"-1/4" (0.3cm-0.6cm) above the PA
cover. Turn on the heater and begin the reflow cycle. Heating time
should not be less than two minutes.
Once the part has reflowed, before trying to remove the PA, carefully
lower the circuit board holder as follows:
• Loosen the thumbscrew on the shaft of the circuit board holder,
• push the spring-loaded holder down and away from the heat-focus
head, and
• retighten the thumbscrew with the holder in the bottomed
position.
Grab the PA with a large pair of tweezers and remove it from the circuit
board. Let the circuit board cool for approximately two minutes. Then
remove the circuit board from the circuit board holder.
if necessary, add solder to the PA ground plane on the printed circuit
board. Then clean each PA lead solder pad on the circuit board to
ensure alignment of the new RF PA. Prepare the sight by using solder
wick and a soldering iron to remove all solder from the solder pads.
Clean the solder pads with alcohol and a small brush. Dry and inspect.
Ensure that all solder is removed.
Once the preparation is complete, place the circuit board back in the
circuit board holder. Add solder paste flux to the ground plane and to
the leads' solder pads. Once the flux is applied, place the new RF PA on
the circuit board, making certain that the PA heatsink sits flush on the
board. Position the heat-focus head over the RF PA and lower it to
approximately 1/8"-1/4" (0.3cm-0.6cm)) above the PA cover. Turn on
PA Cover
Leads
Slab
Solder
Pads
49

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