Mobile phone BGA welding

Mobile phone BGA welding

With the volume of the mobile phone is more and more small, it is more and more high degree of

integration of the internal and phones are now used almost all of ball grid array packaging module

and that is what we say normally BGA. This module is welded on the motherboard in the form of

patch.. For maintenance personnel, skilled master hot air gun, as a compulsory course to repair

this module.

1. The degree of heat resistant BGA module and temperature of the heat gun control techniques, BGA

encapsulation of the entire bottom module used to connected to the circuit board.Not by welding tube feet,

but the use of solder ball to welding.Module to reduce the volume, mobile phones are relatively narrow the

volume, but also the packaging form of the module determines the easy to the characteristics of virtual

welding, mobile phone manufacturers in order to reinforce the module, often using glue method.This

increases the maintenance difficulty.To deal with this kind of glue sealing module, we need hot air gun to

blow for a long time to remove the modules, often in the process of blowing welding, desoldering

temperature control is not good, the module down also damaged because of the temperature is too high.

So how to effectively regulate the temperature of the air pressure gun.To disconnect the module and not

damage!Told everyone several models commonly used in the heat temperature and welding of BGA module

should pay attention to matters.MOTOROLA V998 CPU, you must be very familiar with it, most of this kind of

module is encapsulated with glue.The heat degree is higher, the module of temperature of the air pressure

gun won't damage it is generally not more than 400 degrees, we can adjust the air pressure gun when the

desoldering temperature to 350-400 degrees, uniform on the surface of the heating, while waiting for the

CPU has a tin ball out, under the instructions of solder has dissolved, then you can move it gently with forceps,

and security.No more than the welding method of the module of the module also use nokia 8210/3310 series

of CPU, but the CPU encapsulation adhesive is different, you should pay attention to when the desoldering

sealant for the damage to the pins on the main board.Siemens 3508 audio module and a 1118 CPU.The two

modules are directly welded on the main board, the heat resistant level is very poor, but they generally difficult

to withstand temperatures above 350 degrees, especially 1118 CPU. When welding generally not more than

300 degrees.We can welding to put a piece of broken on the good CPU CPU. Thus reduce damage caused

direct blow welding module.Blow welding time may be longer, but the success rate will be higher.

2. The motherboard above a bit after the remedies.Maintenance of friends at first, in the open encapsulated

with plastic module, will certainly encounter a bit on the main board.Like a lot of solder joints is not over,

we can do it in the attachment point method to repair, the repair this bit of failure, I use green oil temmoku

companies as a curing agent for fixed connection.

Motherboard off point there are basically two kinds, one kind is can see pins on the motherboard, such better

handle some wire welding on the pin directly, keep a proper line into a circular placing it on a bit position,

another kind is a solder hole type, this kind of difficult to deal with some, use a knife to dig out the following

pin first, then made the size of the solder wire circle, on the location of the bit.Plus a solder ball, heat with air

pressure gun.So that the circle and pins together.Next is to use green oil curing, besmear is on processing

good bonding pad, with a magnifying glass on the condenser under the sun for a few seconds, the curing

degree is better than a day heat with heat gun.Motherboard off solder joints, we even better, with lines after

clean.In fixed or insulation need coated with green oil, get outside, use a magnifying glass as the sun

concentrated green oil.A few seconds curing.

3. The bonding pad on a bit of welding method.Welding plate, after a bit before welding plate is cleaned,

the strikes a little way on the module of rosin, then on the bonding pad, be careful not to put too is, mean

to put a little bit crooked, but don't crooked too much, then heated, modules, such as the following tin ball

melts, the module will be automatically reset to the welding plate, welding should pay attention to don't

swing module.In addition, when planting tin, if the solder paste is too thin, can take out a little on a napkin,

the flux to the absorption of paper, the solder paste is good!