[SOLVED]820-2915-a no power, no green light

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andrew boren

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this board works with a third party charger, found that out when fixing it, but does not turn on with a genuine apple charger, green light comes on for a split second then goes off. my guess is that the U7000
is not recognizing the charger, but im at a loss on how to check what has went out . because the charger wont turn on, all i get is 1-2v anywhere, this board came in with a dead mag-safe, blown f6905, blown off the board c9000. replaced it all and it worked with my third party charger that at the time i didn't know was a third party charger. "replaced the charger with a genuine charger already"
 

andrew boren

New member
wish i had a fake charger still, we got rid of it once we found out it was fake, the customer fried theirs using a fake charger.

i will test voltages at thoes locations tomorrow when i get back into work
 

andrew boren

New member
changed out u7000 with a board that has a bad gpu, but still powers, still nothing, tho i was confused, i removed u7000 and the green light still comes on on the bad gpu board. yet on the board im working on it wont come on. i dont have a fake charger to test it out. what am i missing?

is there a way to test Q7080?
 

dukefawks

Administrator
Uhm, take the board with the bad GPU to Apple for a free repair.....
Get a fake charger for trouble shooting.
 

andrew boren

New member
with or without u7000 i get no 3v42 power , green light for one second then it goes off, and wont come back on unless i leave it unpluged for a few min
 

dukefawks

Administrator
Short on PPDCIN, 3V42? Also remove F7040/41 without U7000 you risk getting the full adapter voltage on PPBUS!!
 

andrew boren

New member
the mac works with a third party charger, at least it did, if i had a short wouldnt it never have worked? it i remove the fuses 7040 and 7041 i shouldnt get any power since PPBUS_G3H would be disconnected to the system.
 

larossmann

Administrator
Staff member
Remove F6905. Place 18.5v from a real bench power supply on pin 2 of F6905. Then plug known good 85w charger in with known good dc in board. If it works, Q7080 is bad.

If you do as duke says and get a knockoff charger this will be easier to troubleshoot.
 

andrew boren

New member
ok so even putting in 18.5v in on pin 2 of f6905 and plugging in the 85w apple charger, did not give a green light. i do have a fake charger on its way, praying its fake, spending less than 20$ on it and it has no apple logo. lol, is their any more testing i can do before the new charger arrives?
 

andrew boren

New member
ok got the fake charger, ppbus_h3h is 12.56. what else should i check?
R7005/21/22 all have power, r7005 is 18.5, r7021 is 19.03 and r7022 is 19.03
 
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dukefawks

Administrator
Not really, you can remover the gate resistors and then test if both FETs open and close. Check on youtube how to test a FET. The gate needs to be disconnected from everything to do that.
 

andrew boren

New member
awesome well next time ill have an idea how to test that little package. thank you, can i get you to close this thread please and thank you for all your help
 
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