Macbook Pro 13 A1278 EMC2555

[ciki]

Hi Macbook wont turn on fan just on and off ,have green light on charger ,

[highpulse]

Re: Macbook Pro 13 A1278 EMC2555

try making a SMC AND/OR PRAM reset first of everything , then let us know , in case you dont know how to do it

SMC reset require no power on board , no battery and dc attached to machine , for 40 second , during this time press a few times on off button .

pram reset - press command + alt +p +r and keep pressing does keys while you press on off , keep the keys pressed , once you hear the reboot and second chime noise , release all keys .

[ciki]

Re: Macbook Pro 13 A1278 EMC2555

It not work When I connect charger it constant on off but when is on battery when I press power button makes only 2 sec fan spinning and thats all,black screen no post no beep

[dellxps15]

Re: Macbook Pro 13 A1278 EMC2555

mainboard code ? 820-xxxx ?

[ciki]

Re: Macbook Pro 13 A1278 EMC2555

Hi its 820-2879 Intel i7
What Im was thinking that problem is one of the current sensing capacitor ,because its cut power just second after start

[ciki]

Re: Macbook Pro 13 A1278 EMC2555

Sorry correction about logic is 820-2936-B

[dellxps15]

Re: Macbook Pro 13 A1278 EMC2555

voltages on bios pins ?

[ciki]

Re: Macbook Pro 13 A1278 EMC2555

3.3v

[highpulse]

Re: Macbook Pro 13 A1278 EMC2555

wich pins have 3.3 ?

[cvorke]

Re: Macbook Pro 13 A1278 EMC2555

I have the similar problem, same board...
It came with PPBUS_G3H shorted to GND at Q7035.
I have changed Q7035 ang got green light and fan as well.
But unfortunately I have no display, chime, anything...
Also tried to power on without RAM and it runs in same way, no beeps...
When I plug the charger with battery inserted, green light go off after couple of sec and no orange light came on. So I have SMC_BC_ACOK at U6901 without battery and not with battery connected.
I tried with changing U7000 - same...
On BIOS i have 3.3 at pins 1,2,3,7,8.