Chip Component Replacement; Over-Molded Pad-Array Carrier (Ompac); Ompac Removal; Ompac Replacement - Motorola GTX/LCS 2000 Service Manual

Chip Component
Replacement
Over-Molded Pad-Array
Carrier (OMPAC)

OMPAC Removal

OMPAC Replacement

2-4 Basic Maintenance
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.
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" 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.
ASFIC U0201 is an OMPAC. It must be kept in a sealed bag with dessicant in the
bag (in a "dry box" as supplied by the Motorola Parts Department prior to use. If
the OMPAC is ambient for an unknown amount of time or for more than 96 hours,
then it must be baked for at least eight hours at 260 ˚ F (185˚ C).
If neighboring OMPAC components are heated above 365˚ F (185˚ C), they will
suffer die-bond delamination and possible "popcorn" failure.
During all repair procedures, heating neighboring components can be minimized
by:
• Using upper heat only. using the correct size heat-focus head, approximately
the same size as the carrier being replaced.
• Keeping the heat-focus head approximately 1/8" (0.3cm) above the printed
circuit board when removing or replacing the device.
To remove the OMPAC, select the R-1070A Air-Flow Station and the
appropriate heat- focus head (approximately the same size as the OMPAC. Attach
the heat-focus head to the chimney heater. Adjust the temperature control to
approximately 415˚ F (215˚ C) 445˚ F (230˚ C) maximum. Adjust the airflow
slightly above the minimum setting. Apply the solder paste flux around the edge
of the OMPAC. Place the circuit board in the R-1070A's circuit board holder, and
position the OMPAC under the heat-focus head. Lower the vacuum tip and attach
it to the OMPAC by turning on the vacuum pump. Lower the heat-focus head until
it is approximately 1/8" (0.3cm) above the carrier. Turn on the heater and wait
until the OMPAC lifts off the circuit board. Once the part is off, grab it with a pair
of tweezers and turn off the vacuum pump. Remove the circuit board from the R-
1070A's circuit board holder.
To replace the OMPAC, the solder pads on the board must first be cleaned of all
solder to ensure alignment of the new chip carrier. Prepare the sight by using
solder wick and a soldering iron to remove all solder from the solder pads on the
circuit board. If a power desoldering tool is available, it can be used instead of the
solder wick. 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 R-1070A's
circuit board holder. Add solder paste flux in the trench of the flux block and
spread it using a one-inch putty knife. Flux the OMPAC by placing it in the trench
of the flux block. Once the flux is applied, place the OMPAC on the circuit board,
making certain that it is oriented correctly on the board. Position the heat-focus