Apple Macbook Pro A1278 no Power

[raajkumar]

Hi,

I have a apple macbook pro A1278 i5. Its having some problem on SMC. I replaced it. Thereafter its keyboard also having some problem by short keys. I replaced it also. Now it won't power on. I try to switch on through smc switch bypass. but No use. i checked the voltages of smc is 3.461V is there. i checked isl 6259 chip also the voltages were right according to schematic. is there anyone to help me please. I updated the attachments with Schematic, Boardview file and Board viewer.

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

I checked the board and i found a small cap C2810 nearby to U2800 is marked as PPVRTC_G3H has rusted by humidity or something was shorted. I checked with ohm meter it shows 0 ohms. i replaced it. but it is not power on.

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

Is there anyone to help me ?

[katfish]

Re: Apple Macbook Pro A1278 no Power

Check some power rails -

PPDCIN_G3H
PP3V42_G3H
PPBUS_G3H
PP5V_S5
PP3V3_S5

And also check -

PM_SLP_S4_L
SMC_BC_ACOK
SMC_RST_L

Problems in RTC can also be an issue. Any other corrosion besides that cap?

Post back with your findings.

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

Thanks for your reply. I couldn't find any corrosion in any area than that cap C2810. I replaced with a new one. i will check all other points that you asked and get back to you.

[keeney123]

Re: Apple Macbook Pro A1278 no Power

Thanks for your reply. I couldn't find any corrosion in any area than that cap C2810. I replaced with a new one. i will check all other points that you asked and get back to you.

If the voltages look good perhaps the bios program is corrupt. So this would require a Bios Flash.

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

Hi Katfish

I checked following power rails

PPDCIN_G3H - 17.01V
PP3V42_G3H - 3.47V
PPBUS_G3H - 12.51V
PP5V_S5 - 4.98V
PP3V3_S5 - 3.32V

And also checked -

PM_SLP_S4_L - 0V - Here only i couldn't find any voltages
SMC_BC_ACOK - 3.325V
SMC_RST_L - 3.438V
RTC_RST_L - 3.316V

Any Suggestions.

[lorins_core]

Re: Apple Macbook Pro A1278 no Power

Can i see A Clear Picture of mobo. then maybe on Soldering installation. but I wont to see first... Have power then no power happen?

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

This is happen after i replaced the bios chip. Before that i lost password for this one. Thereafter i got a new programmed bios chip. after i replaced it it worked fine. but after few switch on it has keyboard short sound. i replaced the keyboard also. after i replaced the keyboard it worked only one time. thereafter it started itself and worked very slowly. i shut it down and try to switch on but it won't. thereafter i checked mobo for corrosion and i found a cap C2810 has corrosion and it was shorted when i check it shows 0 ohms. i replaced it but i still have the same. it is not power on. i try SMC switch by touching that two pads with 3.478V and ground. But no use.

[katfish]

Re: Apple Macbook Pro A1278 no Power

Hi Katfish

I checked following power rails

PPDCIN_G3H - 17.01V
PP3V42_G3H - 3.47V
PPBUS_G3H - 12.51V
PP5V_S5 - 4.98V
PP3V3_S5 - 3.32V

And also checked -

PM_SLP_S4_L - 0V - Here only i couldn't find any voltages
SMC_BC_ACOK - 3.325V
SMC_RST_L - 3.438V
RTC_RST_L - 3.316V

Any Suggestions.

Does the charger get a solid green light?

PM_SLP_S4_L is a requirement to enable S3 power rails. Then S3 power rails are required to get into an S0 state, or computer on. Without it, you're not going to power on.

PPDCIN_G3H seems low as well. Looking for 18.6 on that. 17 may be enough, but I'm not 100% sure there. Anyone know?

PPBUS_G3H at 12.6 would indicate SMC is on. When it's down to 12.2 then SMC is not coming up. 12.51 should be ok.

PM_SLP_S4_L is a pain in the butt. Could be a number things keeping it low. Including a bad SMC, bad PCH, bios (or related) issues .... are any of those voltages you checked "jumping" or fluctuating? Or are they all steady?

[highpulse]

Re: Apple Macbook Pro A1278 no Power

give me board code , ill send you correct bios for your platform , you got all signal for the motherboard to run .
for the power on does mac , well does board run between 16.5 and 18.5 .
as katfish sayed , chek for flutuation on the main lines , but if computer haad password issues and you replaced bios , then all issues started after that thing , then your bios is the issue , tell me board code 820-xxxx-x and i'll sent you a good working dump

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

Thanks for the quick reply. My Mother board code is : 820-2565-A and the EMC number is :2555

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

give me board code , ill send you correct bios for your platform , you got all signal for the motherboard to run .
for the power on does mac , well does board run between 16.5 and 18.5 .
as katfish sayed , chek for flutuation on the main lines , but if computer haad password issues and you replaced bios , then all issues started after that thing , then your bios is the issue , tell me board code 820-xxxx-x and i'll sent you a good working dump

Sorry for late reply. Because today only i received my programmer TL866CS. I reflash it with Ala_Borbe's file. But It is not working it still not powering up. All voltages are correct is there anyone having any idea.

[dellxps15]

Re: Apple Macbook Pro A1278 no Power

check bios voltage before and after pressing smc bypass. check also for 5 volt if present.

main voltages required are:

12.5 volt
3.4 volt
5 volt
smc reset _l voltage, 3.3 volt smc power
3.4 volt on smc_onoff
bios voltages on pin 1-2-3-5-6-7-8

try with only mainboard + magsafe+ ram. as u plug power supply, macbook should power on itselt. obviously no battery connected.

im working atm on smc read and programming, but its a bit complicated and is taking me lots of time

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

i will check and update you

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

check bios voltage before and after pressing smc bypass. check also for 5 volt if present.

main voltages required are:

12.5 volt
3.4 volt
5 volt
smc reset _l voltage, 3.3 volt smc power
3.4 volt on smc_onoff
bios voltages on pin 1-2-3-5-6-7-8

try with only mainboard + magsafe+ ram. as u plug power supply, macbook should power on itselt. obviously no battery connected.

im working atm on smc read and programming, but its a bit complicated and is taking me lots of time

PPDCIN_G3H - 17.01V
PP3V42_G3H - 3.47V
PPBUS_G3H - 12.51V
PP5V_S5 - 4.98V
PP3V3_S5 - 3.32V

And also checked -

PM_SLP_S4_L - 0V - Here only i couldn't find any voltages
SMC_BC_ACOK - 3.325V
SMC_RST_L - 3.438V
RTC_RST_L - 3.316V

And On the bios chip are
Pin 1 - 3.311V
Pin 2 - 1.636V ( This one only fluctuating up and down )
Pin 3 - 3.317V
Pin 4 - 0V
Pin 5 - 3.303V
Pin 6 - 3.299V
Pin 7 - 0V
Pin 8 - 3.318V

Is these Ok.

[dellxps15]

Re: Apple Macbook Pro A1278 no Power

3.3volt bios comes after pc power on...... or smc problem or bios problem

ps: fan doesnt spin right ?

remove bios chip, and then connect power supply. check if fan spin.

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

i removed it but fan not spinning

[raajkumar]

Re: Apple Macbook Pro A1278 no Power

I think i need to replace smc. Do i need to get pre programmed SMC and also i found two types is it same ? F2117LP20H V and F2117RVPLP20HV . My Logic board have F2117RVPLP20HV.

[dellxps15]

Re: Apple Macbook Pro A1278 no Power

it could be a bad smc. u need a second hand smc from a spare board.