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[solved]820-2915 U3900 BCM57765B0 Shorted... Hot as hell...

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wrbailey

wrbailey

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So, this is the same 2011 15" computer. Have it running "fine" however, after I was about to run tests on the board, I touched the Broadcom BCM57765B0 chip and it is boiling hot. Actually at first, I touched the other side of the board, behind the BCM chip and couldn't figure out why some components were getting very hot, with no rhyme or reason. Then I felt the other side of the board (had to remove the speaker assembly, then it was obvious)

So my question is... do I try to replace that chip, or do i just remove it from the machine entirely? On the schematic, it even says "OMIT" above U3900, what does that infer? Looks like it is the SD card reader/LAN IC (which I don't care about so much Card Reader or LAN)

If I were to "remove" this chip from the board, what would one recommend? This has around 70 "pins" and would seem to be a beast to remove/reinstall... which I am willing to try, but...

Any way. If it were you, what would you do and how would you go about doing "it"?

Thanks again!!!

**** JUST looked up the BC57765 and it is the Card reader IC, and LAN***
 
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wrbailey

wrbailey

New member
So I removed the BCM chip... no more hot spots on the board.

BUT... when I was going through all the rails to make sure they were present, the PP15V_T29 is "missing"
Schematic says, duh, Vout = 15V... I am only getting 0.485V on C3897... Is T29 the thunderbolt circuitry? I plugged in a thunderbolt to HDMI and it outputs to my monitor just fine... grey screen with ? Folder...

Is something wrong? Will PP15V_T29 only show up under certain conditions, or do I have something wrong with the T29 Power Support circuit?

Thanks!!
 
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