Motorola HT-1000 Service Manual page 68

To Remove a PBGA Component,
46
If neighboring PBGA components are heated
above 365 degrees F. (185 degrees C.), they will
!
suffer die-bond delamination and possible
"popcorn" failure. To prevent this delamination
problem, circuit boards to be repaired must be
C a u t i o n
baked in an oven for eight hours at 260 degrees F.
(125 degrees C.) prior to solder repairs.
All pad-array carriers in these radios, except for
!
the IF IC (U3), are PBGA components. Prior to use,
all PBGA components must be kept in the sealed
bag (with moisture-indicator card) as supplied by
C a u t i o n
the Motorola Parts Department. Once the sealed
bag is opened and/or the PBGA component
subjected to ambient humidity (for an unknown
amount of time or for more than 96 hours) then
that PBGA component must be baked in an oven
for at least eight hours at 260 degrees F. (125
degrees C.)
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"-1/4" (0.3cm-
0.6cm) above the printed circuit board when removing or
replacing the device.
select the R-1319 Rework Station and the appropriate heat- focus head
(approximately the same size as the PBGA. 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 the solder paste flux around the edge of
the PBGA. Place the circuit board in the circuit board holder, and
position the PBGA component under the heat-focus head. Lower the
vacuum tip and attach it to the PBGA component by turning on the
vacuum pump. Lower the heat-focus head until it is approximately 1/
8"-1/4" (0.3cm-0.6cm) above the carrier. Turn on the heater and wait
until the PBGA component 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-1319's circuit board holder.