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820-4924-A .430ma no fan, no chime, no boot

2click

2click

Member
Hi, I have this board which I dont know what else to do to it, I get all_sys_pwrgd but get no chime, and no image on it. When I connect it to the magsafe 2 (original magsafe 2 85watts, no adapter 1->2) I get a green light, and then it turns orange, no fan or chime...
ppbus_g3h = 12.60
pp3v42_g3h= 3.42
all_sys_pwrgd= 3.3v

In adition to this, and because I got stuck diagnosing this board, can you please help me sending me a document or link to the explanation of the power on sequence on the macbooks? I can fix back light, ISL issues and some others, but this is the 3rd month I am using the forum and I really dont think I have learned a lot from it, I really want this to work, but I need help to learn this stuff... thank you...
 
2informaticos

2informaticos

Administrator
Staff member
The fan will not start oon this board untill CPU gets really hot; is the normal behaviour.

Do you get CPU VCORE (C1031)?
Did you check for USB activity?

The forum goal is to help online in the repair process.
I'm sure you can also learn a lot only taking notes from the threads.
For personal training, please contact forum staff...
 
Last edited:
2click

2click

Member
Do you get CPU VCORE (C1031)? r= 1.87V
Did you check for USB activity? THE PSU GOES TO .558MA and I get no light on an external USB drive... Update: I connected an USB mouse and it does not turn on...
I´m stuck here... Please help, it´s my computer, the one that I use to see all the schematics and vb´s....
thank you!
 
Last edited:
2click

2click

Member
PLT_RESET_L = 0v
when I first connect it it goes to .430 ma, then it goes down to .020 ma and then it turns on again and goes to .430 but doesn´t restart anymore...
 
2informaticos

2informaticos

Administrator
Staff member
That means the power on sequence is not completed.
Check PM_PCH_PWROK and PM_PCH_SYS_PWROK.
Akso check CPU_VCCST_PWRGD.
 
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