2. Conformally
Coated Components:
2.1 A detailed
repair process for Conformal Coated 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 68-80309F92, available from
Motorola APD or APE.
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 component is removed by setting the Chipmaster
to the removal temperature as explained below, (5.0) and using
a probe supplied in the kit, gently pry each corner of the component
as the coating starts to break down under temperature, (Illustration
# 3), be careful not to apply too much pressure so as to damage
the component 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 # 81-30303-E45, APE # 8100-1097, 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, APE # 8200-1500.
Illustration
# 3
3. Required
Materials:
Item
Description APE Model # Motorola Model #
1. Chipmaster
8100-1003 R1319A (110V) or R1321A (220V)
2. SMT Tweeze/Solder Iron EX-755 R1366
3. SMT Tool Kit 8100-1097 01-80303E45
4. Nozzle for QFP208 8100-1414 66-80332E92
5. Chipmaster Manual 8100-0609 68-8309F40 (Supplied with Item
1)
6. Lint Free Antistatic Wipes 8200-1500
7. Hand 2.3 Dioptic Magnifier 8200-1200
4. Selecting
the correct Profile.
The Chipmaster
8100-1003, includes the optional Profile Storage Controller,
which includes four (4) carefully designed and pre prepared
profiles for most BGA and QFP/SMT applications, (Illustration
# 3a). In reworking QFP 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).
Illustration
# 3a
To select
Profile # 2, from the "Operator View Display"
(Illustration # 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.
Illustration
# 4
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