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|iPhone, iPad, iPod Hardware Repair Hardware Repair discussions for iPhone, iPod , iPad & Apple Products, help, guides.|
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|05-10-2013, 13:09||#1 (permalink)|
Join Date: Aug 2011
Thanks Meter: 0
4S wifi replace chip (advanced user)
I have replace many BGA chips in the past, but now i just started with replacing 4S wifi chip.
Removing was not much of an issue, making it hot enough (330 °C) did the job well. The pads are in excelent shape. I clean up the PCB, added flux and soldered a new chip (with presoldered pads) onto it with my BGA solder machine. The maximum temperature i reached in the solder frofile dit not get higher then 250 °C (60 seconds) to not damage the chip. The chips i used starts all with SS22 but then have different numbers, seems like a serial number. I canot find the type, though footprint seems fine.
The repair did not work, still greyed wifi (no water damage, plain no wifi fault after ios update).
My questions :
a) i did some investigation , got the new chip out of the pcb and see that there was still hars residu on the PCB, though very thin, i guess 0.05mm- 0.01mm , but maybe still enough to make false contact? How do i remove all residu under the chip?
b) Can it be the chips that are faulty / wrong ? Strange there is no type number on it.
c) any other advice?
Very thankfull in advance
|05-14-2013, 16:29||#3 (permalink)|
No Life Poster
Join Date: Apr 2009
Thanks Meter: 2,517
If you use too much heat solder will short between and cause grayed no wifi,try give less heat from the bottom of the board not from top of wifi ic.
There are 3 types of wifi module ic 2 used in iPhone 4S 1 type used in iPhone 4G CDMA i not think problem in wifi serial number.