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820-2879 green and orange light, stuck white screen and wont power on from battery

P

protocold

Member
- Screen stuck at white screen, "chime" with magsafe, green light and orange light is observed when known good battery is plugged in.
- Same stuck at white screen when battery is removed.
- Wont power on when attempt to use battery only.
- Wont response to keyboard i.e. cannot do nvram reset or hold option key etc etc (but tested keyboard is good with other board)
- Harddrive is removed, sometimes it will go to flashing folder icon after waiting for a very long time.

- Checked LCD itself is good with known good board.
- Checked memory is good.
- Board is clean with no water damage.

where should I look?
 
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2informaticos

2informaticos

Administrator
Staff member
Check voltage for pins 2/3 of J9000; bad L9004?

Post PPBUS_G3H and 3V42_G3H voltage with battery alone.
Did you try known good battery?
 
P

protocold

Member
L9004 is good.

With good known battery alone:
PPBUS_G3H = 11.37v
3V42_G3H = 3.38v
No fan spin, no chime.

do i need to simulate the power button? it seems like this board wont power on by itself?
 
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P

protocold

Member
Sorry i think i had wrong observation before, I spent more time on isolating the issue.

It seems like the problem is J3401, if the cable is connected to J3401 on the board, the machine will just stuck at white screen (with chime).

As soon as i took off the cable at J3401, the board seems to boot up ok.
 
2informaticos

2informaticos

Administrator
Staff member
There are more device connected.
You should find which is the culprit.
Can be power rail, or data problem.
First disconnect the other end of airport flex.
If still the same, remove L3405 and check again.
You can test removing L3404 too.
 
P

protocold

Member
Without the flex cable, the machine boot up normal (apple logo is shown almost immediately and then the boot proceed)

If I keep the flex cable in, but disconnect the other end of airport flex cable, the machine will still boot up, but will take a long time for it to show the apple logo to finish the booting. iSight camera is working under this situation.

Now the weird thing is...now after I reconnect the other end of airport flex cable, the machine still boot up (also takes a long time for apple logo to show up and boot), but bluebooth is not presence. Wifi and iSight works.

What causes the slow apple logo symtoms?
 
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P

protocold

Member
i have done that equivalently by masking the 2 bluetooth data pins (pin 24&25) by tapes and the slow apple logo problem is gone. Now what? I guess data problem causing by the flex cable?
 
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P

protocold

Member
no, i dont have another airport card here to test, but the problem is there with or without the airport card when the cable is plugged into the logic board.
 
P

protocold

Member
OK, perhaps it isnt worth the effort to take apart the screen to replace cable.... so maybe it is best to just disable bluebooth 2.0 at the moment as it is old anyway....

Is there an easier way out?
 
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