MacBook Pro 2010 820-2879-B won't start

[Roman78]

I got a broken MBP here. The PSU-LED is on green when connected and the orange when the battery is connected. So it is charging. Now when I press the power button or shortage the Power-On-Pads on the logicboard, the fan starts to rotate for a split second. Looks like the power immediately breaking down.

I just downloaded the schematics and the brd-file of the board.

Are there some known issues whit that board? This behaviour look familiar, the 17" 2008 and 2009 had this also whit the C7771 Cap which powered the GPU, but the 13" does not have a dedicated GPU.

What could it be? What to measure next?

[piernov]

Re: MacBook Pro 2010 820-2879-B won't start

C771 is only on some 15" and 17" boards indeed.
Any history? Liquid damage, etc…
Tried with everything disconnected except DC-in board and fan?

[Roman78]

Re: MacBook Pro 2010 820-2879-B won't start

The owner reported the device was not booting the OS. Hangs during boot. He removed the HDD, connected the HDD to a USB-Device and copied the data of it. This was working. He reassembled the HDD into the MBP and tried a reinstall, this failed. So he removed the HDD again and bought a SSD. After he assembled the SSD the MBP does not power up any more.

I completely disassembled the MBP. I tried other RAM, PSU and Battery.

[piernov]

Re: MacBook Pro 2010 820-2879-B won't start

Sounds strange. Look closely on the board for any liquid damage, damaged or knocked of component.
You don't need a battery to troubleshoot it. Not even RAM if it's shutting down right away.
If there is no hint at all, first measure resistance to ground on PP3V42_G3H (board cold, all power drained from it, can give a clue about a dead MCP).
Then check charging circuit current sensing (resistance between pins 17/18 and 27/28 of U7000).

[Roman78]

Re: MacBook Pro 2010 820-2879-B won't start

So here am i again, and finally had some time to experiment a little.

So PP3V42_G3H to ground resistance is kind of rising. Stated with 160 Ohm and now after some minutes it is on 1.25KOhm.


But what do you mean with the last measuring?

The 2 resistors are those two in the red circle.

On point CHGR_CSI_P (pin 28) I have 16V and on CHGR_CSO_P (Pin 18) i have 12V.

Battery is charging. It is just not turning on.

[piernov]

Re: MacBook Pro 2010 820-2879-B won't start

Measuring resistance between the 2 sets of mentioned pins of U7000.

Anyway resistance to ground for PP3V42_G3H doesn't look good. Make sure all power is disconnected and let the board sit for a short while to be sure it is fully discharged and cold then check again.

[Roman78]

Re: MacBook Pro 2010 820-2879-B won't start

OK. after some time without any power on it i get 17,3KOhm at the PP3V42_G3H.

And between pin 18 and 28 on the U7000 i got 60 KOhm

[piernov]

Re: MacBook Pro 2010 820-2879-B won't start

17.3 kohm to ground on PP3V42_G3H sounds more reasonable. Should be a bit higher but probably still ok.

It is between pins 17 and 18 on the one hand, and between pins 27 and 28 on the other hand.

[Roman78]

Re: MacBook Pro 2010 820-2879-B won't start

Ah, ok. I got those 2 now.

17-18 = 3.2 Ohm
27-28 = 20.7 Ohm

[MobileXT]

Re: MacBook Pro 2010 820-2879-B won't start

I got a broken MBP here. The PSU-LED is on green when connected and the orange when the battery is connected. So it is charging. Now when I press the power button or shortage the Power-On-Pads on the logicboard, the fan starts to rotate for a split second. Looks like the power immediately breaking down.

I just downloaded the schematics and the brd-file of the board.

Are there some known issues whit that board? This behaviour look familiar, the 17" 2008 and 2009 had this also whit the C7771 Cap which powered the GPU, but the 13" does not have a dedicated GPU.

What could it be? What to measure next?

If you have a green light on a charger then check your SMC_RESET_L U5010 pin 5 make sure you have a 3.3v there. if you do, move to the PPBUS_G3H power rail make sure you a 12.54v there at F7040. if you read below 12.54v then you have a SMC issue.

[piernov]

Re: MacBook Pro 2010 820-2879-B won't start

You have that backwards. He has green light on Magsafe (and it even goes to orange when charging the battery), so the SMC is working properly and it also means SMC_RESET_L is present.
We could always confirm the voltage on PPBUS_G3H though, but I don't think it would be wrong.