Preparations Of Rework; Removing Of The Module; Welding Area Treatment - Huawei MU509 Series Hardware Manual

HUAWEI MU509 Series HSDPA LGA Module
Hardware Guide

6.9.2 Preparations of Rework

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6.9.3 Removing of the Module

The solder is molten and reflowed through heating during the module removing
process. The heating rate must be quick but controllable in order to melt all the solder
joints simultaneously. Pay attention to protect the module, PCB, neighboring devices,
and their solder joints against heating or mechanical damages.
Figure 6-7 Equipment used for rework

6.9.4 Welding Area Treatment

Step 1 Remove the old solder by using a soldering iron and solder braid that can wet the
solder.
Step 2 Clean the pad and remove the flux residuals.
Step 3 Solder pre-filling: Before the module is installed on a board, apply some solder paste
to the pad of the module by using the rework fixture and stencil or apply some solder
paste to the pad on the PCB by using a rework stencil.
Issue 09 (2014-03-06)
Remove barrier or devices that cannot stand high temperature before rework.
If the device to be reworked is beyond the storage period, bake the device
according to Table 6-1 .
 The LGA module has many solder pads and the pads are large. Therefore, common
soldering irons and heat guns cannot be used in the rework. Rework must be done using
either infrared heating rework stations or hot air rework stations. Infrared heating rework
stations are preferred, because they can heat components without touching them. In
addition, infrared heating rework stations produce less solder debris and less impact on
modules, while hot air rework stations may cause shift of other components not to be
reworked.
It is proposed that a special clamp is used to remove the module.
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