Apple MBP 13" 820-2936 not Load Battery

[Roman78]

I got a Apple MBP 13" here with a failure on the Power Rail. It is not charging the battery and not working on PSU. It only works on Battery. The PSU light is green or off. When i remove the battery the MBP goes out immediately.

I found those two topics:

https://boards.rossmanngroup.com/thr...harging.32412/

https://de.ifixit.com/Antworten/Anse...harged+battery

I measured pin 17-18 and 27-28 on the U7000, those are 3.3 Ohm and 20 Ohm, Just like in the the first link. So i replaced the U7000 with one of a spare board but with no success. So in the first topic someone replaced the Q7030, how to i measure that thing? The diagram looks like the picture added.

In the second topic they are replacing a resistor going bad, but mine ist still at 0 Ohm.

[piernov]

Re: Apple MBP 13" 820-2936 not Load Battery

The PSU light is green or off.

Please clarify, the state of the LED on the Magsafe is very important.
Also before replacing anything you have to take some voltage measurements.

[Roman78]

Re: Apple MBP 13" 820-2936 not Load Battery

So, now i have some time for this older MBP. The LED is green, mostly, but at some time it just turns off.

What should i measure? Power incoming is 16v

[piernov]

Re: Apple MBP 13" 820-2936 not Load Battery

If Magsafe LED is green but sometimes not present it's most likely bad contact. Known good Magsafe and DC-in board should take care of that.
You have to measure the main power rails such as PP3V42_G3H and PPBUS_G3H with battery disconnected. I'd recommend watching Louis Rossmann videos as this topic is already covered extensively, probably even a very similar problem on the same board.

[luckydip]

Re: Apple MBP 13" 820-2936 not Load Battery

As piernov said watch Louis's videos on the one wire circuit - you need a steady light on the magsafe before moving forward.

[Roman78]

Re: Apple MBP 13" 820-2936 not Load Battery

The green light sais on for now.

PP3V42_G3H = 3,34V
PPBUS_G3H = 0,08V But it is slowly rising. Now at 0,10V So there could be the problem.

The device is turned of at this time of measuring.

I checked the rossman forum, not the videos yet.

[Roman78]

Re: Apple MBP 13" 820-2936 not Load Battery

So i found this video: https://www.youtube.com/watch?v=wPxYPrnoMZ4 there he replaced the U7000, just as i did. Well i took it from a broken board.

[piernov]

Re: Apple MBP 13" 820-2936 not Load Battery

There's a lot more to the troubleshooting process than randomly replacing a component.

[luckydip]

Re: Apple MBP 13" 820-2936 not Load Battery

So i found this video: https://www.youtube.com/watch?v=wPxYPrnoMZ4 there he replaced the U7000, just as i did. Well i took it from a broken board.

You need to measure voltages on U7000, also check for a short on PPBUS_G3H

[Roman78]

Re: Apple MBP 13" 820-2936 not Load Battery

The voltages look normal except the PPBUS_G3H. What voltages should be on the U7000? There should not be a shortage, because it is working from the Battery. When the Battery is connected the PPBUS_G3H is around 11 Volt.

What voltage should be on the SMC_BC_ACOK? But the light is green. I followed the steps in the Video and all seems the same issue, low PPBUS_G3H around 1 Volt, no voltage on the Q7030 and on the white Fuse (which is directly connected to the PPBUS_G3H).