Motorola HT-1000 Service Manual page 67

Chip Components
Plastic-Ball Grid-Array
(PBGA), Over-Molded Pad-
Array Carrier (OMPAC), and
Glob Top Components
plastic switch housing to ensure that it has not warped due to
overheating.
2. While holding the RF switch bracket firmly against the RF board:
• VHF and UHF radios - solder the two leads of the housing to the
solder pads on the RF board.
• 800MHZ and 900MHz radios - bend the two tabs around the side
of the RF board as close to the board edge as possible to hold the
bracket down tightly.
3. Insert the new RF switch spring and RF switch piston into the RF
switch assembly. The contacts of the piston should be facing the
gold-plated pads of the RF switch board. Once the spring and
piston are inserted into the RF switch, they will be retained by the
switch.
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.
1. To remove a chip component, select a hot- air hand piece and
position the nozzle of the hand piece approximately 1/8" (0.3cm)
above the component to be removed. Begin applying the hot air.
Once the solder reflows, remove the component using a pair of
tweezers. Using solder wick and a soldering iron or a power
desoldering station, remove the excess solder from the pads.
2. To replace a chip component using a soldering iron, select the
appropriate micro-tipped soldering iron and apply fresh solder to
one of the solder pads. Using a pair of tweezers, position the new
chip component in place while heating the fresh solder. Once
solder wicks onto the new component, remove the heat from the
solder. 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.
3. To replace a chip component using hot air, select the hot-air hand
piece and reflow the solder on the solder pads to smooth it. Apply
a drop of solder paste flux to each pad. Using a pair of tweezers,
position the new component in place. Position the hot-air hand
piece approximately 1/8" (0.3cm) above the component and begin
applying heat. Once the solder wicks to the component, remove
the heat and inspect the repair. All joints should be smooth and
shiny.
The term Plastic-Ball Grid-Array (PBGA) will be used to describe most
of this products type of modules. PBGA modules may be the
construction of an Over-Molded Pad-Array Carrier (OMPAC)
component or "Glob Top" component. A U204 synthesizer
component in one radio may be an OMPAC and the same U204
synthesizer in another radio may be a Glob Top. The two components
look a little different, but are electrically the same and are
interchangeable.
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