SMC Issue on MBP 13 - Hardware Troubleshooting Guide

[miguecor]

MBP 13" 2011 fading out randomly

Hi, I'm not sure if this is the right place to post this question, but I was reading your thread and seems to be full of experts (what I'm not).

I have a MBP 13" late 2011 which is fading out (like going to sleep) randomly. It goes for 5 to 10 seconds and then it comes back on again. Sometimes it does it 3 or 4 times within a minute.

I've been trying to reset the SMC, but the described procedure in the apple support links doesn't seems to work.

I think maybe I did it in the past, but now it's not working. Does the procedure change after the first time you reset the SMC? Are there any more optional procedures to reset the SMC?

Do you think that the fading out issue maybe due to dust on the board?



Thanks in advance!

 

[Gromerpyle]

Did you check the capacitor(s) stabilising the VCC? Otherwise trace the 3.3V line back to: alternate ROM support section and PP3V3_S5_ROM at the power supply (U7200). In other words, is there 3.3V anywhere on the board and if so, find the place where it stops along the line.

I know, I make it sound easy Happy measuring!

thanks for your reply.

I have not measured the capacitors. they are hard to find and measure. I have no borad view of my logicboard 820-2530. Anyway, I've got 3.3v at u7200 I think. it was late last night =). I'll try some more tonight.

/ calle

 

[rvanpruissen]

thanks for your reply.

I have not measured the capacitors. they are hard to find and measure. I have no borad view of my logicboard 820-2530. Anyway, I've got 3.3v at u7200 I think. it was late last night =). I'll try some more tonight.

/ calle

This might help, good luck!

 

[Dadioh]

Hi, I'm not sure if this is the right place to post this question, but I was reading your thread and seems to be full of experts (what I'm not).

I have a MBP 13" late 2011 which is fading out (like going to sleep) randomly. It goes for 5 to 10 seconds and then it comes back on again. Sometimes it does it 3 or 4 times within a minute.

I've been trying to reset the SMC, but the described procedure in the apple support links doesn't seems to work.

I think maybe I did it in the past, but now it's not working. Does the procedure change after the first time you reset the SMC? Are there any more optional procedures to reset the SMC?

Do you think that the fading out issue maybe due to dust on the board?



Thanks in advance!

When you say it "fades out" is it actually going to sleep with the sleep LED glowing? Or is the backlight fading out (i.e. screen going dim)?

If it is the screen going dim then try an external monitor connected to the Display Port. If that stays on then it would seem to be an issue with the backlight.

If it is actually going to sleep then it could be the Battery Indicator Light cable which also contains the sleep sensor.

 

[Gromerpyle]

This might help, good luck!

Thank you. perfect now can measure a little more precise. just noticed the lack of a small component of my logicboard. I will be back with pictures.

/ calle

 

[Southwest]

I do have low voltage. I have what you might call "leakage" coming from the magsafe giving pins 2&4 on DCIN board, pins 1&2 at DCIN jack, and the fuse near the DCIN jack ~0.19 volts. Same is true for areas on the board where PPDCIN_G3H inputs.
I get this same sort of "leakage" coming from the battery as well, giving battery pins 7-9 and pin 5 of Q7055 ~0.20 volts, but pins 1-3 of Q7055 and the battery fuse are ~0.12 volts. The ares on the board where PPBUS_G3H inputs are also ~0.12 volts.
The whole rundown is in my previous post( post #1268) but long story short I traced the PPDCIN_G3H and PPBUS_G3H to the common cathode diode D6990. I measured the 0.19 volts of PPDCIN and 0.12 volts of PPBUS at there respective anodes but got nothing coming out the cathode, which is where U6990 gets the signal that tells it to enable G3HOT (PP3V42_G3H) on this model board, 820-2936. You can find this on pg.63 of the schematic I attached to post #1268.
Now I thought that because G3HOT isn't being enabled that there would be NO signal back to the magsafe through pin 5 of DCIN jack/ pin 3 of the magsafe to tell it to release the full ~16.5 volts or so. Therefore, causing the voltage to drop off as is seen on my board. Same goes for the battery. How could the battery be enabled by the SMC if there is no 3.425 volts from PP3V42_G3H to power the SMC? It seems as if the battery, and I suppose the magsafe as well, goes into shutdown mode because this cycle can't be complete.
It seems like a rare case, but I think the reason why BOTH the battery and magsafe, which are known functional ones, aren't giving the board there full power is because of this D6990 diode. But I really don't know how to confirm this theory, and I don't want to start soldering off parts on a whim and risk permanently damaging the board. So now I'm here on this forum to see what you all think.
I apologize for rambling on again. I'm sorry Musicsoul but I'm not familiar with the wled driver. Hopefully the schematic I posted can help you get info on it. Two whole views of my board are attached below. See post #1268 for a close up of D6990.

Water damaged 1278 13" looking for Board View for a 820-2936-B.

 

[funtotos]

a1278 no power

Hello,
I am French, excuse me for my english very bad
I have a macbook pro water damaged.
A1278 no power, does not start
how to test smd components with multimeter
red circle bad components

thank you very much
----------

 

[jmb84]

MBP 13 (Mid 2012)

Hi

I have a liquid damaged MBP 13 (Mid 2012) that I've managed to restore, however I'm getting some intermittent power issues. I received the computer in the following state:
- Would not turn on
- Magsafe LED was very dim/faint
- Nothing appeared to work

I opened it up and removed the logic board and cleaned it thoroughly in Isopropanol to remove the evident liquid and corrosion. This seemed to work and the computer sprung back to life.

Once I'd restored it, the laptop appeared to be working fine except the battery's capacity did look to be low (when looking at the system report within OS X).

After leaving the computer turned off for several days I went to turn it on and nothing happened - would not turn on and the dim LED on the Magsafe had returned. With some more playing around I managed to get the Magsafe LED green again, however it would not turn Orange (not charging). I could boot up and see that the system was reporting that no battery was installed.

After shutting down again – the dim Magsafe LED comes back and again I can’t turn on the computer. I can play around and do random things and then all of sudden it might boot up, but it’s very intermittent.

I can’t find the schematics and/or brd files anywhere for the mid 2012 MBP 13” (P/N 820-3115-B) which is making it difficult to diagnose to problem. DOES ANYONE HAVE THE SCHEMATICS AND LAYOUT FILES FOR THIS LOGIC BOARD.

Any ideas on what the problem might be would be very much appreciated.

Thanks in advance.

 

[Southwest]

That part looks like a cap and it seems to be related to the Realtek sound circuit. Would need to see a schematic to be certain but I doubt it would be related to the charging circuit failure.

0.1ohms across a fuse is fine. What do you get when you touch the tips of the meter together? My meter usually shows about 0.4ohms so that is about best case you can ever expect. A fuse will either be a few ohms (Good) or Megaohms (Blown). Nothing in between.

For dim charge LED alsways start at charger IC pin 14. If that is not 3V then you will not get a green LED. If it is 3V then at least the charger is OK and the issue is between that signal and the magsafe connection. There are a few components to check there.

----------



U6901 pin 5 is G3HOT so if you have 0V there you should be dead on the entire logic board?

Basically your AND gate U6901 has no power so the SMC_BC_ACOK signal is not passing through to U6900. Double check U6901 pin 5 and, if it is really 0V I think you need to check the solder connections on that device and replace.

Finally received and replaced U6901. Thank you for all your help, just checking to see if you know all the Voltages around both U6901 and U6901
Here is what I have on U6901
1 3.25v
2 3.25v
3 GND
4 3.25v
5 3.25v

 

[mousetail]

A1181 random shutdowns

Hi. First post although I’m a regular reader. This thread is an incredible resource.


I’ve got a 2006 MacBook 1,1 A1181 with the dreaded Random Shutdown Problem.

Don’t know the history of the machine but it looks like it was never taken back to Apple for repair and has been mothballed for a very long time. Looks almost new and the battery is reporting 170 cycles, although it is dead and unusable.

Powered by the magsafe lead it will boot and run normally for about 15 minutes and then shutdown with an audible click.

It will only re-boot if the magsafe is disconnected for a few seconds and then replaced. Typically it will then run for about 5 minutes.

Subsequent re-starts shutdown earlier and earlier, until eventually it only gets halfway through the chimes!


Thinking at first it was a temperature issue, I have done the following:-

complete strip down and cleanup;
new thermal paste;
replaced heatsink (old one had cracked board at the sensors);
renewed and re-routed the heat sink temp sensor leads;
PRAM reset;
SMC check;
HD check and repair permissions;
RAM reseat.

The temps reported to iStat are all low/normal. CPU has never reported above 80°C. Occasionally heat sink 2 reports 126°C briefly before stepping down to around 40.

Starting up with the ‘temporary bypass’ from Dadioh’s original post makes no difference, except that the fan continues at high speed after shutdown until power is removed.

Console logs don’t seem to show anything unusual, at least nothing common to each shutdown.


I know this is MacBook ancient history and that Apple replaced/repaired back in the day. Does anyone have any ideas about the cause, or about what I try next?

All contributions gratefully received…thanks

 

[rvanpruissen]

Schottky didn't help

...

Hi all,

The quest continues: adding the missing Schottky diode (see post 1471) has not fixed my problem , but there's power on pin 2 of the charger IC (U7000), unlike before.

The situation:

• G3HOT is ehm, HOT
• 16,5V present from charger
• Voltages on charger chip as indicated in image (no value mean 0V (IC only))
• Q7000 drain = 0V
• Drumroll......... NO CHARGING LIGHT, NO CHIME, NO SCREEN, NO NUTTIN'

Bit lost a the moment, so please help!


This bit leaves me with a few questions:

1. Is the voltage after R5087 a reference voltage which is pulled down whenever it is 'thought' the charger is not present or faulty?
2. Which IC pulls this signal down normally and when? Something to do with AMON right?
3. Should the Q7000's drain be hot in the current situation or should the gate signal be low for this? (I always confuse my FETs , I think it's the latter)
4. Shouldn't there be voltage on VDD and VDDP? If so, where to look?

Thanks guys, any help is appreciated for this mechanical engineer

Rick


PS Is there some kind of attempt on explaining ISL6258A somewhere, or even the total MBP power logic sequence?

 

[mihkels]

Mid 2010 A1278 MBP random freezing

I've got a mid 2010 13" MBP that freezes randomly. It's definitely not a software problem as ASD reports a faulty sensor. It's the "TN1D MCP 0 Die" sensor with a "Sensor is reading below the low limit" error. I understand that TN means it's got something to do with the northbridge temperature sensor.

I replaced the thermal paste but that didn't help. Checked with iStat and northbridge temperatures seemed fine - in the high 50s and low 60s.
I checked the motherboard but didn't know where to look for the temperature sensor.
The computer works fine in EFI mode of Apple Service Diagnostics but crashes randomly in OS X.

Any help?

Picture of the error:

 

[Dadioh]

I've got a mid 2010 13" MBP that freezes randomly. It's definitely not a software problem as ASD reports a faulty sensor. It's the "TN1D MCP 0 Die" sensor with a "Sensor is reading below the low limit" error. I understand that TN means it's got something to do with the northbridge temperature sensor.

I replaced the thermal paste but that didn't help. Checked with iStat and northbridge temperatures seemed fine - in the high 50s and low 60s.
I checked the motherboard but didn't know where to look for the temperature sensor.
The computer works fine in EFI mode of Apple Service Diagnostics but crashes randomly in OS X.

Any help?

Picture of the error:
[url=http://i.imgur.com/fvDYHfz.jpg]Image[/URL]

The sensor is the MCP "Die" which means it is a thermal diode on the silicon die itself. Sounds like whatever pins the Northbridge uses to provide that silicon temperature are affected. Or the Northbridge itself has failed in this respect.

 

[mihkels]

The sensor is the MCP "Die" which means it is a thermal diode on the silicon die itself. Sounds like whatever pins the Northbridge uses to provide that silicon temperature are affected. Or the Northbridge itself has failed in this respect.

Any possibility to disable this sensor software wise? Probably not.

As the problem is with the Northbridge itself, I guess a reball is needed.

 

[Dadioh]

Any possibility to disable this sensor software wise? Probably not.

As the problem is with the Northbridge itself, I guess a reball is needed.

Before you go the reballing route you should doublecheck the schematic to see if the signal from the Northbridge goes through a device on the logic board. Like some sort of muxing device. If it does then that could be the failure point. If the signal goes directly to the SMC then it could be the Northbridge or it could be the SMC.

 

[mihkels]

Before you go the reballing route you should doublecheck the schematic to see if the signal from the Northbridge goes through a device on the logic board. Like some sort of muxing device. If it does then that could be the failure point. If the signal goes directly to the SMC then it could be the Northbridge or it could be the SMC.

Unfortunately, I don't have access to this kind of devices nor the skill to use them.
Upgraded the EFI Boot ROM to the latest, "MBP71.0039.B0E (EFI 2.5)" version. Seems to have fixed the freezes for now.

 

[macattack600]

a1278 NonPro backlight shorted? No boot

13 a1278 NonPro Unibody

If you place your finger with just battery installed over the circled area on motherboard the backlight will light full up on lcd without the macbook turned on. The board will power on twice and powers on the solid sleep light won't go further.

All voltages are correct on fuses and some fets , charges battery. Will startup once in SMC debug with solid sleep light no chime.

Does anyone think the short around these fets/component are feeding another short in line from SMC to prevent from booting? Or even if this is actually shorted or may just do this from conductivity from my finger always (I will later check the wled driver but I believe it's working)




I have boardview file and schematic for this model have been checking components but if anyone has an idea what fet or area to maybe test or any advice thank you.

 

[kennethf]

Macbook Pro 13 2010 A1278 EMC:2351

Good job providing detailed info.

The only supply that will have a voltage at this point is the 3.3V supply as you have noted. The 5V, CPU, etc... will not be enabled until the power sequencing has progressed to that point. However, your board is not getting out of the starting gate. It is good that you have G3HOT so that at least the basic circuitry comes up like charger and basic SMC function but the SMC is detecting something wrong and not allowing power sequencing to proceed.

Have you tried the SMC bypass method described in the first post? If that also is not working then there are quite a few different things that could be wrong so no simple step by step is possible. Detailed diagnostics required.

Hello

I have found something wrong, all capacitors on (PPVCORE_S0_...) are shorthed. Could this be one or more defective caps or is there something more that can make this happen?

Thanks Kenneth

 

[rvanpruissen]

Hello

I have found something wrong, all capacitors on (PPVCORE_S0_...) are shorthed. Could this be one or more defective caps or is there something more that can make this happen?

Thanks Kenneth

Aren't those in parallel? If so, you're measuring only one short on serveral points. Assuming you didn't desolder them.

 

[peislander]

Thanks your answer.

I found the faulty of the logic board. This is an amplifier IC, which drives the loud speaker. It was short-circuited and it didn't allow to wake up the macbook. I replaced it today since then it has worked fine.

Hey
Can you please tell me exactly what IC you replaced.I got one with no chime or sound.
Thanks

 

[kennethf]

Aren't those in parallel? If so, you're measuring only one short on serveral points. Assuming you didn't desolder them.

Hello

Yes thay are in parallel so Iam going to desolder one by one and mesure. But wondering if this could happen if other components in its circuite were damaged what is symptoms when a CPU are broken?

Thanks

 

[rvanpruissen]

Hello

Yes thay are in parallel so Iam going to desolder one by one and mesure. But wondering if this could happen if other components in its circuite were damaged what is symptoms when a CPU are broken?

Thanks

There might be a component in series with all the capacitors. If you desolder this, you can isolate the problem to the capacitors or further back in the power supply.

Please note that I'm also newbie here, so maybe you need a more die-hard mac-analyst to shed some light on this issue.

 

[rvanpruissen]

Hi all,

The quest continues: adding the missing Schottky diode (see post 1471) has not fixed my problem , but there's power on pin 2 of the charger IC (U7000), unlike before.

The situation:

• G3HOT is ehm, HOT
• 16,5V present from charger
• Voltages on charger chip as indicated in image (no value mean 0V (IC only))
• Q7000 drain = 0V
• Drumroll......... NO CHARGING LIGHT, NO CHIME, NO SCREEN, NO NUTTIN'

Bit lost a the moment, so please help!


This bit leaves me with a few questions:

1. Is the voltage after R5087 a reference voltage which is pulled down whenever it is 'thought' the charger is not present or faulty?
2. Which IC pulls this signal down normally and when? Something to do with AMON right?
3. Should the Q7000's drain be hot in the current situation or should the gate signal be low for this? (I always confuse my FETs , I think it's the latter)
4. Shouldn't there be voltage on VDD and VDDP? If so, where to look?

Thanks guys, any help is appreciated for this mechanical engineer

Rick


PS Is there some kind of attempt on explaining ISL6258A somewhere, or even the total MBP power logic sequence?

Anyone? Pleeeaaaassseeeee?!

 

[laptech]

M97 Magesafe 'no led' fixed

Hi, my first post. Just wanted to firstly say many thanks to the many of you who have contributed lots of useful information in here. I have been reading this thread for many weeks now and from the information contained within, I have managed to fix 3 A1278 M97 boards that would not power on using the magsafe. The faulty part was Q6910, which I ordered from Digikey and arrived today. I am so chuffed that they are now working. I had an idea of where the fault might be but never having repaired apple laptops before i had no idea if what i was doing was correct. This site has allowed me to put those doubts to one side.

The company I work for is trying to get into the repair of Apple laptops, using my many years experience of component level repairs of non-apple laptops. The range of laptop my Boss is buying is vast, we currently have the complete range of A1278's, other laptops including 13', 15' and 17' including some i5 and i7 series units. We also have some Macbook Air's. Once the current stock gets repaired, he buys in a new batch, all faulty of course, waiting then for me to repair them. As I said, i am not experienced with apple laptops so I am learning just i like alot of you are. I am also not an electronics guru so I would not be able help with electronic questions but what i do have is a vast range of apple boards that i can help with pictures, voltage readings, other measurements. Like the majoriy of you, all i have to work with is a multimeter.

I dont have board views or schematics, my boss is a bit tightfisted when it comes to spending money so i have to make do with what i can find on the internet, but what i do have is working boards, plus complete units that i could take electronic measurements from if need be.

This site has helped me and I would like to repay that help as much as i can. I will do my best in helping people where i can but please remember that my time is limited as I have a job repairing laptops to do so replies to help/queries might not be as quick as some would like.

Hopefully I will have a good time here, helping others as well as improving my knowledge on apple laptops.

regards
Roger

 

[laptech]

Anyone? Pleeeaaaassseeeee?!

Hi, i've got a couple of same model boards with the same fault as yours. I am currently working on them so if i find any useful information as i progress through the repair, i will let you know.

Rog