820-2915-B Green light no power

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tlon19

New member
hey guys i was wondering if anyone could help me, i have 820-2915-b no water damge, i have read from several articals that the isl6259 chip goes bad on this randomly. so i changed the isl6259 chip and i get a green light now, but when i short the power button pads nothing happens no fan spin no chime nothing, any help would be appricated, can send a tip with bitcoin.
 

dukefawks

Administrator
These power on by themselves without a battery.
First take measurements, what voltage is on L7030? Should be 12.6V, if not check R7051/52 and R7021/22 also check R7005.
 

tlon19

New member
thanks for the reply duke. hope this helps

L7030
V 12.61

R7051 0.791
R7052 0.4

R7021 10.1
R7022 10.4

R7005 224.8
 

george-a

Member
R7005 should be 20ohm and if I remember correctly if that is fucked U7000 is also fucked.. which is baffling since you have 12,6V

R7051 should be 2.2ohm
R7052 should be 0ohm... these two are for current sensing and should give proper readings.

R7021 - R7022 seem good.
 
Last edited:

tlon19

New member
hey george

i replaced the r7005, now it read 20 ohm, also wanted to note that r7051 was reading 0.7 ohm i replaced that also now it reads 2.2, any more suggestions?
 

dukefawks

Administrator
Yes that is a GPU issue. If the board looks somewhat clean and unmolested I would take this to Apple under the exchange program and not mess with it myself.
 

Allstartek

New member
Hello. I have been working on an issue very much like this one. Originally I had no power, no lights at all.
I Replaced U7000 now I get a green light but no boot, fans etc.
I've been back and forth so many times that I really am completely lost now. It 'seems" like I have power every where that I should.
Would you please assist me?

I followed the info in the beginning of this post and these are the results I get..

L7030
pin 1 12.65V
pin 2 12.65V
pin 3 0v

R7051 12.65v
R7052 12.65v
R7021 16.09v
R7022 16.09v

R7005 16.42
 
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