Macbook Pro a1502 no power

[harshana]

Laptop worked perfectly without any issue. suddenly it got stuck and died. I have no idea about the issue. I tried to troubleshoot the issue and I found below things.

I can see 16.57v from magsafe adapter.
I see 12.6v on L7130
also 3.3v on L7560

I can't see 5v. I guess thats the issue. but I can't see any short to ground on that coil. (tested at L7520)

I guess 5v enable signals are missing. please help me to troubleshoot this.

Here I attach the diagrams and brd files I used.

[dellxps15]

Re: Macbook Pro a1502 no power

hi. check if j6100 has corrosion post voltage on c7505 pin 1, u6100 voltage, u1950 voltage and check if l7520 is pulsing 5 volt.

green light on magsafe right ?

[reformatt]

Re: Macbook Pro a1502 no power

This can be so many things. Can be a missing pre-requisite for PM_SLP_S4, or a short on a sub-rail after S4.

The 820-4924 board I've found is pretty robust. It's often minor corrosion spots caused by insects (either dying and decomposing, or from their droppings). A close examination of the board looking for corrosion spots is often the first thing to do, especially around the top of the board near the CPU. Most issues are usually on the keyboard facing side BTW. You are looking for discoloured end caps of resistors/caps usually. Don't forget to look at the sides of IC's as well, especially U7200. I had one recently where CPU_PROCHOT_L pin had crap on it, and S4 wasn't asserted as a result.

[harshana]

Re: Macbook Pro a1502 no power

hi. check if j6100 has corrosion post voltage on c7505 pin 1, u6100 voltage, u1950 voltage and check if l7520 is pulsing 5 volt.

green light on magsafe right ?

green light appears for few seconds and turn into orange. sometimes I can't see any light. (this can be charger issue. I had this issue for last few months)

I can't see corrosion anywhere.

No 5v pulse at L7520. will check other voltages and post soon.

[harshana]

Re: Macbook Pro a1502 no power

This can be so many things. Can be a missing pre-requisite for PM_SLP_S4, or a short on a sub-rail after S4.

The 820-4924 board I've found is pretty robust. It's often minor corrosion spots caused by insects (either dying and decomposing, or from their droppings). A close examination of the board looking for corrosion spots is often the first thing to do, especially around the top of the board near the CPU. Most issues are usually on the keyboard facing side BTW. You are looking for discoloured end caps of resistors/caps usually. Don't forget to look at the sides of IC's as well, especially U7200. I had one recently where CPU_PROCHOT_L pin had crap on it, and S4 wasn't asserted as a result.

I will have a look again.

[piernov]

Re: Macbook Pro a1502 no power

https://logi.wiki/index.php/User:Pie....2C_what_do.3F

[harshana]

Re: Macbook Pro a1502 no power

hi. check if j6100 has corrosion post voltage on c7505 pin 1, u6100 voltage, u1950 voltage and check if l7520 is pulsing 5 volt.

green light on magsafe right ?

c7505 pin 1 --------> 5.03v
u6100 pin 8 ---------> 3.35v
u1950 pin 8 ---------> 3.44v
l7520 --------> 0v

[harshana]

Re: Macbook Pro a1502 no power

https://logi.wiki/index.php/User:Pie....2C_what_do.3F

When I read this article, I guess I must find another magsafe charger before make a decision. I can see batteries are getting fat. (but I can see 12.57v using batteries as well)

what do you think? is that enough voltages I mentioned above replies to move forward or do I need to find another AC adapter???

[mon2]

Re: Macbook Pro a1502 no power

I can see batteries are getting fat.

Not good - gases are expanding and will cause at least the casing to deform. Have seen it with clients in our shop. Also dangerous for the end user. This pack needs to be replaced.

See attached.

L7520 enables through voltage on pin #4 of U7501.

What is the voltage to ground of pin #4 on U7501 ?

[harshana]

Re: Macbook Pro a1502 no power

Not good - gases are expanding and will cause at least the casing to deform. Have seen it with clients in our shop. Also dangerous for the end user. This pack needs to be replaced.

See attached.

L7520 enables through voltage on pin #4 of U7501.

What is the voltage to ground of pin #4 on U7501 ?

U7501 pin 4 -----> 0v

[mon2]

Re: Macbook Pro a1502 no power

Review this webpage if PM_SLP_S4_L is LOW = 0v.

See case # 2 on this website.

https://www.it-tech.com.au/mac-q-a/pm-slp-s4-l-timing/

Do check the voltage to ground on both sides of R8179. Is it 0v on both sides?

Continue to update this thread.

[harshana]

Re: Macbook Pro a1502 no power

Review this webpage if PM_SLP_S4_L is LOW = 0v.

See case # 2 on this website.

https://www.it-tech.com.au/mac-q-a/pm-slp-s4-l-timing/

Do check the voltage to ground on both sides of R8179. Is it 0v on both sides?

Continue to update this thread.

both sides on R8179 is 0v. means PM_SLP_S4_L = 0v

PPVRTC_G3H = 3.34v
RTC_RESET_L = 3.34v
PCH_SRTCRST_L = 3.34v
PCH_INTVRMEN_L = was unable to find a testpoint to test Low signal(PCH_INTVRMEN = 3.24v)
PCH_DSWVRMEN_L = can't find a testpoint to test Low(PCH_DSWVRMEN = 3.24v)
SYSCLK_CLK32K_RTCX1 = don't have an oscilloscope.
PP3V3_S5 = 3.34v
PM_DSW_PWRGD = 3.44v
PP3V3_SUS = 3.35v
PM_BATLOW_L = 0.03v
PM_RSMRST_L = 3.31v
PM_PWRBTN_L = 3.43v (batteries not connected)

[mon2]

Re: Macbook Pro a1502 no power

BATLOW is often missing because of bad/incorrect charger....

Be sure your adapter is suitable.

[harshana]

Re: Macbook Pro a1502 no power

Be sure your adapter is suitable.

I'm using my original charger. but well damaged. will try to find similar one and test.