A1286 mid 2010 820-2850-A logic board was repaired from Apple. One chips is missing

[soyo]

A1286 mid 2010 820-2850-A logic board was repaired from Apple

They tried to charge my friend 500$ for the repairing of coffee damage. But He gave up to repair. Now I found they had done something on it. One chips is missing. Please see the red shape of the following pictures. Please tell me what kind of chips has been taken by apple.

 

[Intell]

Some machines have a TI 51125 IC chip there. Depending on the machine revision, it is supposed to be vacant.

 

[soyo]

Some machines have a TI 51125 IC chip there. Depending on the machine revision, it is supposed to be vacant.

Obviously they did soldering on this area so that the fan connector or slot edge is burned a little bit. I saw there is a chip in Apple Mac book Pro Technician Guide document and other pictures. I'm sure there is a chip.

Is there somebody can post a PCB layout picture? I have schematic diagrams of 820-2850. I just want to know what chip is. Thanks

 

[soyo]

If it's TPS51125, it's a SYNC_MASTER=K18_POWER. It provides 3.3V 7.2A max output and 5V 9.1A max output.

It's critical in the schematic diagrams document. Please give me more confidence. I will reseat this chip.

Wow....... I found many places are using this 3.3V (tag PP3V3_S5). This should be a main power. Are you sure it's here?

 

[Intell]

Some revisions of the 820-2850-A logicboard do not have that. I'm holding one right now that looks just like yours and it is in a boxes straigt from Apple and labeled as "New".

 

[soyo]

I confirmed this chip is TI 51125 from a brand new motherboard. Many thanks to Intell!!!! Good man.

I will reseat one 51125 and try to fix it.

 

[goMac]

Nothing needs to be fixed here. Apple makes these sorts of changes all the time.

It's possible if the chip is not supposed to be there on this board revision, you will damage the new board.

It's also very likely this new board is NOT your original board. It is likely a different revision refurbished board.