820-2883 no green light

Yoel Ren

Member
Came in with many dust at the back of the logicboard, magsafe showing dim green light
R6905 is smoking when connected to magsafe,there’s hole on d6905 too
I have replaced r6905, unfortunately i dont have d6905 so i used u6901 from donor board (820-2879), when connect magsafe i have brief green light but after that, suddenly i don’t have any green light (not even dim green light), there’s no voltage at pp18v5 fuse, so this looks like mosfet issue , is q7050 the problem?
 

2informaticos

Administrator
Staff member
Check diode mode at C6990/99 and F6905.
Be sure the fuse is still good.
Also post exact ohm value R7010/11 and R7001/98.
 

Yoel Ren

Member
Diode mode on c6990 0.189
C6999 0.292
Fuse resistance is 0.3 ohm so, good
R7010 7.3kohm
R7011 7.1kohm
R7001 55kohm
R7098 106kohm
 

2informaticos

Administrator
Staff member
You didn't post diode mode at F6905.

Check if board works with fake charger, or lab power supply.
In such case, leakage issue is bypassed.
 

2informaticos

Administrator
Staff member
But do you get voltages on the board???
Is better to use a lab power supply, connected through 85W cable.
 

2informaticos

Administrator
Staff member
Only that???

"voltages on the board???"
I expected more readings; at least 3V42 and PPBUS_G3H...

Post U7000 voltages; pins 1, 2, 3, 9, 12, 14, 15, 17, 19, 20, 27.
 

Yoel Ren

Member
sorry i was in hurry when replying this msg.. here’s the reading..
Ppbus_g3h 0v
Pp3v42 : 0v
U7000 pin 1: 0v
2: 16.4v
3: 3.9v
9: 0v
12 0v
14 0v
15 200mv
17 0v
19 5v
20 5v
27 9.3v
 
Last edited:

2informaticos

Administrator
Staff member
Post exact resistance (ohm mode) between pins 17/18 and 27/28 of U7000.

"27 9.3v"
This is really strange.
Check first Q7000; also Q7001 if still low...
 

Yoel Ren

Member
Resistance is 3.5 and 20 ohm,
So normal
After replacing q7000 and q7001, here’s the reading
Q7000 pin 1 : 6.2v
2 3 4 : 16.5v
Q7001 pin 1 2 3 4 0v
Pin 5 16.5v
 

Yoel Ren

Member
Now, with original magsafe, i got dim green light, but no voltage at dc in fuse, maybe we can fix the leakage issue, then solve the pp3v42 after that..
 

2informaticos

Administrator
Staff member
Fake charger bypasses the leakage, use it at this moment; untill find the problem.

Q7001 looks bad, or incorrect model.
Be sure to use P-channel MOSFET...
 

Yoel Ren

Member
i replaced q7001, and i have 17.5v at pin 1-5
i have replaced u7000 too, here's the reading with fake charger :
1 : 0
2 : 16.5v
3 : 3.9v
9 : 0
12 : 0
14 : 0
15 : 0
17 : 0
19 : 5v
20 : 5v
27 : 17.9v
 
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