SMC Issue on MBP 13 - Hardware Troubleshooting Guide

ZZZAC said:

check Q7055 and Q7056

The R7058 may indicate a shorted fet across that line or nearby.

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I thank you very much for taking the time to look at it
can you just tell me if i have to desolder the mofsets to check them with a multimeter or if you have a special way of doing it
thanks again.

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ZZZAC said:

check Q7055 and Q7056

The R7058 may indicate a shorted fet across that line or nearby.

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it sounds like your SMC may have failed, it certainly has deteriorate.
if there is no activity atall the only thing you can check is the system RTC, If you get the proper clock signal to the MCP then it should alow the fan to spin, if this signal is missing or incorrect it wont start (this is controlled by the SMC)

checking this is difficult without an Oscilloscope, bu there should be a steady voltage on the clock crystal, usually around 0.8 but dont quote me on that.

Good luck

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grize said:

Thanks for the reply. I'm only getting around 0.04v from one pin on the crystal. No output or input when I check it with the oscilliscope. Is there anything you can suggest to check next?

The magsafe light is turning green, and there are some voltages around the board that seem reasonable but it still isn't powering on or charging the battery.

Thanks

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grize said:

Just rechecked the output from the RTC crystal and I was wrong in my last post. I am getting approx 0.5v from (or to?) the crystal on net RTC_CLK32K_XTALIN.

There isn't any reading on RTC_CLK32K_XTALOUT.

Any suggestions where to look next?

Thanks

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ZZZAC said:

Think it needs to be higher than that, specaily bad if it has no signal from the oscliscope. (i dont own a osclipscope so cant test it)

I know i have one here that works somewhere so ill test the voltage on my board at some point, i have a strong feeling you need to replace the smc chip

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macelek01 said:

Hi South657,

I measured R7402, pin 2 was 12,5V and pin 1 was 0,5V. Do you think it is problem?

Thanks!

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varungargi said:

Also i dont hear the chime as soon as i press the power button or not even after secs it comes like after a min
if i see the logic board i see the fan spins as soon i press the power but it stops for a sec and then starts. it does like this for like 2 times and then i hear the chime sound and then the macbook works fine.

Is it something to do with EFI chip ? I updated to latest EFI SMC Firmware still no change . . .

Any help ?

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grize said:

Ok thanks for getting back to me. I have found that I don't have PP3V3_S0 anywhere on the board.

What is the deal with replacing the SMC chip? I have some scrap boards here but none of them are identical to the one I am working on. If I find one with the same SMC chip, is it safe to swap? Or does it need to come from an identical logic board?

Is there anything else i can test to confirm whether it is the SMC chip?

Thanks

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kokito said:

ZZZAC said:

check Q7055 and Q7056

The R7058 may indicate a shorted fet across that line or nearby.

----------

I thank you very much for taking the time to look at it
can you just tell me if i have to desolder the mofsets to check them with a multimeter or if you have a special way of doing it
thanks again.

Click to expand...

check the resistance across the fet (or from the battery fuse to ground) and it should tell you if the rail is shorting,there are varius ways of finding short circuited components.

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i have this dead annoyig macbook air a1466 (820-3437)

It was liquid damaged, i restored g3hot, i then replaced the wled and polarizer now we have a very nearly full functional laptop.

Problem is small and therefore frustrating. keyboard and trackpad dont respond in OS. it always thinks there's a bluetooth keyboard installed and that means it disables internal trackpad and keyborad.

it does the same with the airport card removed. i figure it must be a dead resistor, capacitor or something on the logic board. Worst part is the trackpad and keyboard works at the os boot loader (where you select the drive you want to boot to)

Anyone have any idea's?
havent taken my multimeter to it yet but i imagine its not going to be an easy fix

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ZZZAC said:

Test to seeif the smc gets voltage right to it (im not talking just about g3h but G3h to the input of the chip.

3.3vs0 and s3 would only apear if the SMC had activated the MCP as the MCP sends signals to activate different power states.

Youd need a reballing stencile to pull one on a scrap board, theres three different firmware versions, you need to be sure you get the same version, the firmware version is indicated by the second line of the chip.
Its a hard job and im not telling you it will definatley resolve your problem, however with charging problems/no liquid damage and symptoms slowly getting worse thats the only thing i imagen it could be.

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bill27 said:

Hi guys, I have this problem with my macbook pro 2011, the previous owner has spilled on it milk, now I have cleaned up the motherboard in the ultrasonic cleaner but now it can't boot.
I have noticed that the charger chip is blown and I have ordered a new one, so I have measured the voltage near contact of battery and I have detected this voltage why?

Image

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mvmanolov said:

Just wanted to post an update for those having similar issues looking for solutions.

I had a repair shop reflow the SMC (i don't have the tools for it) and the thing works flawlessly now... (its been two days)

Good luck all, and many thanks to those who responded

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grize said:

Hey ZZZAC,

Thanks a lot for the reply and the advice so far. I took a gamble and replaced the SMC chip with one from a scrap board, without the use of a stencil. Initially after replacing the chip i was only getting a dim green light on the magsafe and nothing else, so I reflowed the chip and gave it some gentle nudging.

Now things are looking much better! The magsafe lights up green and then orange to indicate the battery is charging. The battery volatage is rising so looks ok there. The RTC crystal is now near 1V. The board still wont power on. It does respond to a SMC reset via the keyboard though, as I can see the magsafe change colour when I release the keys.

Any suggestions where to look next with this one?



Regarding your MBA - Are you able to reset the SMC using an external keyboard? Have you tried booting in to single user mode to see if the keyboard works outside of the OS?

Thanks

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kokito said:

Hi evryone
I have noticed that on Q7031 pin 5 I have 19.02 v with magsafe only and on pin 1,2,3 I have only 1.92 v , while at pin 24 (charg_ugate) of U7000 I have 2.33 v
Can somone please tell me if this is normal.
Thank you

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South657 said:

Hi kokito,

No: looks like u7000 is bad.

south657

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ZZZAC said:

your ic is short, means you probably shouldn't have it plugged in
Its sending the input voltage everywhere maybe.
Also looks like you should check your multimeter. 26.5v isnt correct it should be 16.5v there would be no way to boost the input voltage
dont plug it in untill its been repaired!

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kokito said:

Thanks fo your answer.
Is it hard to change?

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South657 said:

Hi kokito,

Yes: if you have to ask that i would get a pro to do it if its a one off. You may also have other faults on the board as well, the 2 fets that make the 12 volt can fail as well. If you read up on u7000 on this thread you will
then have an idea of how to proceed.

regards

south657

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South657 said:

Hi motechman;

The number is on the side you are looking at, they move it around from year to year it will be on the left hand side from the middle just up
from the ram and as far over to the fan connector and up around the edge of the board by the fan wires. It will be on it for sure.

You need to replace the keyboard so you can do a pram reset you can not do it without that key then that should sort out the fan and
other things that might be wrong.
Also changing the battery would be a good idea they are not much. And if you want to speed things up go for SSD drive.

Regards

south657

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motechman said:

The keyboard has now been replaced. I reset the SMC and the unit seems to boot normally now. However I can't move the mouse pointer and the keyboard seems dead. Before I received the new keyboard I tried to boot an Apple Hardware Tools disk and noticed then the mouse & keyboard were dead. Could not boot AHT CD.

I could plug in externals (mouse, keyb) and then login. I assumed there was something in the SMC that was affecting the keyboard controller and decided to wait until the new keyboard arrived before messing around with the machine anymore.

I'm highly confident I was able to reset the SMC based on the response of the magsafe LED when I hold the control, shift and option keys down upon booting.

With the Mac powered off, the magsafe shows orange (battery is around 95%). No change to that if I just press the power button, which just boots to the login dialog screen. If I hold the shift-option-control keys and press the power button, the magsafe turns green immediately upon releasing the power button and returns to orange 5 - 10 seconds later, and the mac does not start. It doesn't matter if I hold the power button longer; nothing happens until I release it. I can release it after releasing the shift-option-control keys too, no change (as long as I pressed the power button with those keys down it seems to do an SMC reset based on the magsafe LED).

This tells me the keyboard is connected and working, at least in terms of the SMC reset sequence. With the old keyboard in place startup didn't work this way; no matter what keys I held the system always tried to start.

Now that I've done the SMC reset the system starts normally from a single press of the power switch and seems to run normally if I use an external mouse and keyboard. I restored the MacBookPro7,1.plist file that I removed to keep the system from wasting cpu cycles spinning it's wheels, hoping to get the fans restored to normal operation. It didn't work, the system's performance was terrible after rebooting, so I removed the file again. Resetting the SMC did not resolve that issue.

I tried to start the AHT by holding the D key down during boot. It failed if holding the MBP keyboard D key but succeeded if I held the D key on the USB keyboard. External mouse worked fine to select language, and remained OK UNTIL the hardware probe was started and then the mouse froze. That'a as far into the AHT that I could get. Waited for 10 minutes but machine never responded.

I pulled the back cover off and reinspected the connectors for the keyboard and trackpad. They looked OK and were well seated.

I'm at a loss on what to check next here folks. I still haven't been able to find a schematic or layout for my 820-2879B logic board either.

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