2. Conformally
Coated Components:
2.1
A detailed rework and repair process for Conformal Coated smt
smd components is outside the scope of this procedure as they
usually contain smaller lead counts than discussed in this
document, and are usually found in products subject to frequency
of handling and environmental hazards, refer to Motorola
document #6880309F92, available from Motorola APD. See repair
procedures at
www.ape.com for the rework.
2.2
As a summary, if coating exist, it is necessary to carry out a
Eutectic Removal only, the Reflow Removal procedure outlined in
7.0 of this document is not possible. The smt smd is reworked by
setting the Chipmaster to the removal temperature as explained
below, (5.0) and using a probe supplied in the kit, gently pry
each comer of the smt smd as the coating starts to break down
under temperature, (Figure 3), be careful not to apply too much
pressure so as to damage the smt smd or contact area. All the
coating material should now be cleaned from the QFP contact pads
and component leads, (should the component need to be reused),
Use the pad prep cleaner included in the Motorola #0180303E45,
SMD Tool Kit to clean the contact area after removal and use the
knife probes to collect all residues and finally clean with a
lint free Antistatic wipe, #6680334EI4.
Figure
#3
3. Required
Materials:
Item
Description - Motorola Model #
1. Chipmaster - Rl478A
(1IOV) or R1321A (220V)
2. SMT Tweeze/Solder Iron - R1366A
3. SMT
Tool Kit - 0180303E45
4. Nozzle for QFP208 - 6680332E92
5.
Lint Free Antistatic Wipes - 6680334El4
6. Hand 2.3 Dioptic Magnifier
- 6680334E13
4. Selecting
the correct Profile.
4.1
The Chipmaster includes the optional Profile Storage Controller,
which includes four (4) carefully designed and pre prepared
profiles for most BGA and SMD/SMT applications, (Figure 3a). In
reworking smt or smt components greater than 100 lead count
Profile #2, is recommended and will provide the correct
"Temperature Ramp" and "Soak" so as not to stress the component
under repair and protect the adjacent components from
degradation or damage. Should the circuit board be of a heavy
metal or ceramic construction, Profile #3 is recommended, to
increase the calorific energy to the board (Not Temperature).
Figure #3a
4.2
To select Profile #2, from the "Operator View Display" (Figure
4) press the INDEX key on the controller ONCE to enter the
"Operator Menu" then press the INDEX Key, ONCE more, to reach
the "Profile Field"; then press either the "UP" or "DOWN" arrow
to reach the desired Profile, (RED L.E.D. display). Then press
ENTER. Press the INDEX key THREE times to return to the
"Operator View Display". See Chipmaster Manual for complete
explanation of controller and features.
Figure
#4
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