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floridiaan · 05-10-2013, 12:09

Hi Fellows,

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

05-10-2013, 12:09	#1 (permalink)
floridiaan Junior Member Join Date: Aug 2011 Location: Netherlands Age: 48 Posts: 12 Member: 1634546 Status: Offline Thanks Meter: 0	4S wifi replace chip (advanced user) Hi Fellows, 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