SMC Issue on MBP 13 - Hardware Troubleshooting Guide

[cmdrdata]

cmdrdata....thanks for the advice and information.

A new battery was tested at an Apple Service center in the MPB13 and it did not make a difference...still was not recognized.

I left the current battery installed in the MBP for several hours and measured voltage at the solder points and never saw it change at all (meter read to hundredths of volt)....tried it with the MBP shutdown and booted.

I did externally charge the battery to 12.2v and installed it with the unit shutdown and magsafe disconnected. I could see the 12.2v at the solder points and both sides of the main fuse near the battery connector, but it would not boot off the battery. And could get any of the battery status indicator lights to come on when pushing the button.

Located a 2117 chip towards top middle of logic board (far way from the battery connector), but in order to do any continuity checking, I would need to remove the logic board ...not in a position to do that again right now.

Also could not find a 6258A chip anywhere...maybe on other side of logic board? This is a early 2011 MBP13 and does not look like the logic board photos I've seen posted. I should have taken a picture of the logic board (both sides) when I had it out, but simply did not think of it.

So, I will use it as a desktop unit for now....I was going to get a new mac mini, but this is much nicer with the built in superdrive.

Seeing the 12.2v on the ends of the fuses indicates that the V+ power rail from either battery or magsafe is ok. If you look at the schematic, notice that the fuse by the battery (the "output side" labeled PPBUS_G3H is the common point where magsafe derived power or battery power converged. In the schematic b;lock diagram (around page 3), there is a signal called SMC_BATT_ISENSE, perhaps this signal is the one causing the SMC to not seeing the battery and thus preventing it from booting. This signal comes from U5313, a switch/multiplexer that monitors battery discharge. I think the logic that generate this signal is damaged. I would not attempt to remove the SMC unless you have the proper equipment. I have never done it myself and would not do it. One other thing worth trying with JUST BATTERY POWER is the FIRST step in this thread that Dadioh mentioned, bypassing SMC checks to power the system. I hope that step bypass the "battery presence" checking. On the battery power level indicator, I would check the tiny ribbon cable that links the LED assembly to the motherboard. I damaged mine during my attempt to repair my MBP.

I've re-looked at the schematic and concluded that if the battery indicator light (BIL) is not working and the flex cable and connector is not damaged, along with the "X" indicator from the SMC then the problem is that the serial data (SDA) and clock (SCL) logic is the issue to be resolved. Those 8 LED series is driven by the SMC to turn on via the serial data line to indicate charge level. The signal pair I mentioned earlier (SMBUS_SMC_BSA_SDA and CSL) is connected to the battery, the indicator, the SMC and the CHARGER ICs. If you have a logic probe (or oscilloscope), those are the lines to be checked for activity.
BTW, it is not a good idea to use ANALOG voltmeter to measure signal voltages as it has low impedance relative to digital voltmeters. You may not get true reading and also may overload/damage the signal source (drawing too much current).

 

[cmdrdata]

I finally got back to working on my second MBP, model A1260 (early 2008 C2D Penryn, 15" MBP, LED backlight, non-unibody).

These are the symptoms:

1. Normal magsafe behavior (green and orange lites), will charge battery to full charge).
2. I can hear activity (fan and superdrive "kick" at startup, but no "BOING" sound and display totally dark. Sleep LED starts up bright them slightly dim after 2-3 seconds
3. Using the "bypass" method (magsafe+batt, magsafe alone, or battery alone) has the same result with the fan going full speed.
4. Disconnecting components didn't help (RAM, DVD, HD, BT, etc., one at a time and retry)
5. The sleep LED when it dimmed stayed at the same level, not alternating bright/dim as in sleep mode.
6. A few months ago, miraculously it booted ONCE normally, but then after I turned it off, it returned to the same symptom as above.

Anyone here have similar symptom and was able to fix it, and if so, how?
TIA.

 

[jugger18]

That definitely sounds like the Nvidia issue that was common with that generation of MBP. Essentialy weak solder joints on the BGA of the GPU. A reflow should take care of it. Not sure if the extended fix/warranty by apple is still in effect.

 

[cmdrdata]

That definitely sounds like the Nvidia issue that was common with that generation of MBP. ... reflow should take care of it. Not sure if the extended fix/warranty by apple is still in effect.

OK, doing a little research and it seemed that reflow temperatures are between 419°F to 435°F (from room temp to 435°F in no more than 8 minutes). Am trying to decide which one is the better method when/if Apple rejected my request (plan to see an ASP). The class action suit pertaining to this problem has closed (7/2011), however it seemed that Apple is still selectively replacing the logicboard for free. Technically, since mine is early 2008 and Apple has extended the repair program to 4 years, I'm thinking I can qualify before 2012 arrives. Anyways, here are my options (youtube examples):

1. Heat gun
2. Pencil butane torch
3. Baking in pre-heated oven to 425°F

My question on #3: would the other components survive? I think there are plastic parts, e.g., the SODIMM frame and audio jack there and I don't think the oven method would work. Anyone in this group have tried any of the above?
Alternately, any recommendation for a re-ball and re-install service and prices? TIA

 

[jugger18]

Personally from ibooks and xbox 360/ps3's i am a fan of the heat gun. I have baked a macbook in the oven at 375 and saw no adverse effects on any of the plastic.

 

[Papabear60]

While fixing my backlight on my Macbook 13" using your other thread I shorted out the magsafe connector and this component (identified by blue arrow - please ignore the other pointers as I re-used a picture from earlier in your thread) glowed like a Christmas tree for the second it took me to seperate the ac adapter from the magsafe.

My joy from repairing the backlight issue was short lived as this happened shortly after so any help identifying the 6 pin ic would be greatly appreciated as the top all got burnt and none of the markings are left to identify what it was !

 

[Dadioh]

While fixing my backlight on my Macbook 13" using your other thread I shorted out the magsafe connector and this component (identified by blue arrow - please ignore the other pointers as I re-used a picture from earlier in your thread) glowed like a Christmas tree for the second it took me to seperate the ac adapter from the magsafe.

My joy from repairing the backlight issue was short lived as this happened shortly after so any help identifying the 6 pin ic would be greatly appreciated as the top all got burnt and none of the markings are left to identify what it was !

I think that may be one of the devices in the 1-wire Over-Voltage Protection. I was going to ask you what the markings on top of the device were but you said it is burned. I am not at home to check a board but will try and get to that when I get a chance.

 

[Papabear60]

Hmm interesting - You are correct!
I just checked the schematic on page 56 and it maps out so the part number is NTUD3127CxxG in a SOT-963 package- Wow that sucker is tiny .. any ideas where I can get a replacment from??

Just an FYI for the thread the conditions on the logic board are:
Main fuse good with 16V
Board fuse good with 12.8V
G3hot good with 3.42v but no power on normally or bypassing SMC.
No green light on magsafe connector.

I think it is worth while checking this little sucker out as i'm guessing with a liquid spill that shorts out the board (or fat fingers like I had ) then there is a good chance this has blown.
You need really really fine probes but the voltages on this should be
Pin1 GND
Pin2 3.25v
pin6 0v

pin3 1v
pin4 17v
pin5 1v

 

[cmdrdata]

Hmm interesting - You are correct!
I just checked the schematic on page 56 and it maps out so the part number is NTUD3127CxxG in a SOT-963 package- Wow that sucker is tiny .. any ideas where I can get a replacment from??

Just an FYI for the thread the conditions on the logic board are:
Main fuse good with 16V
Board fuse good with 12.8V
G3hot good with 3.42v but no power on normally or bypassing SMC.
No green light on magsafe connector.

I think it is worth while checking this little sucker out as i'm guessing with a liquid spill that shorts out the board (or fat fingers like I had ) then there is a good chance this has blown.
You need really really fine probes but the voltages on this should be
Pin1 GND
Pin2 3.25v
pin6 0v

pin3 1v
pin4 17v
pin5 1v

Try Newark Electronics for chip source. They have similar item (dual, small signal FETs) for replacement part.

I am wondering about your "should be" voltages. How do you determine this? To me it doesn't make sense having pin4 at 17v. To me this should be logic level as it is the serial data line that communicates the magsafe status to the SMC (the reason for magsafe light not turning on).

If your schematic is like the attached picture then:

Pin3 is ADAPTER_SENSE
Pin4 is SYS_ONEWIRE
Pin5 is ONEWIRE_EN(able)

I THINK this comes from the SMC, so it should NOT be 17v. Dadioh, do you concur? I also sometimes wonder for FETs that are normally "always enabled", i.e., the gate signal is pulled up to G3HOT. Would it do any harm if one short the S and D pin together to test the rest of the circuit? My thinking is that FET in this configuration is used as a switch, and thus shorting S and D pins is like us pretending to be an SMC turning them on/closing the switch.

 

[Papabear60]

Thanks for your input - I have learnt a lot from your other inputs in the thread so thanks for chiming in here.

The schamtic I have is different as attached.

I have managed to replace the dual FET Q6910 but still does not power up.
I got the voltages from another Macbook unibody 13" that powers up but only through the SMC debug process as described in this thread whereas my Macbook pro will not power up either way.
So you are right in that these voltages could be wrong but my way of thinking was that this circuit is probably not the reason my other Macbook wont power up and therefore the voltages were probably good?

 

[Dadioh]

Thanks for your input - I have learnt a lot from your other inputs in the thread so thanks for chiming in here.

The schamtic I have is different as attached.

I have managed to replace the dual FET Q6910 but still does not power up.
I got the voltages from another Macbook unibody 13" that powers up but only through the SMC debug process as described in this thread whereas my Macbook pro will not power up either way.
So you are right in that these voltages could be wrong but my way of thinking was that this circuit is probably not the reason my other Macbook wont power up and therefore the voltages were probably good?

Seems to me if pin 6 is 0V then pin 5 = the voltage divider of 470K/180K. In fact the schematic says Vgs = 7.3V @ 20V DCin (running on adapter) and Vgs = 4.74V @ 13V DCin (running on battery). So if pin 6 is 0V and pin 4 is 17V you should not be seeing 1V on pin 5. Probably more like 6.5V. Check those 2 resistors if you are sure teh FET is OK.

 

[destic]

Where can I get this Transistor/FET

Hi!

I've got an similar issue on my 2010 macbook Pro and found out, by comparing my logic board with a functioning one, that there is a Transistor/FET Missing. On the missing Transistor it only says "P7". I attached some Photos of it, I would be very glad if somebody could tell me were I could get one of these!

microscope view:

 

[Papabear60]

The only two ways I know of to identify and get this component is to either get a schematic for the 2010 and get the part number, package type etc directly off the schematic and order it from one of the many suggestions within this thread or get your hands on a dead identical logic board and pull the required component off it. Being that you have a 2010 logic board may make it harder to find one so getting hold of a schematic may be your only hope.
Anyone have the 2010 schematic that can help?

 

[destic]

I found the part on the schematic, its a rclamp2402b it protects the smbus Battery connectors from over voltage

 

[peislander]

Thanks for your input - I have learnt a lot from your other inputs in the thread so thanks for chiming in here.

The schamtic I have is different as attached.

I have managed to replace the dual FET Q6910 but still does not power up.
I got the voltages from another Macbook unibody 13" that powers up but only through the SMC debug process as described in this thread whereas my Macbook pro will not power up either way.
So you are right in that these voltages could be wrong but my way of thinking was that this circuit is probably not the reason my other Macbook wont power up and therefore the voltages were probably good?

Hey,I got a few macbooks that wouldn't power up from power button or the G3 hot.I get lucky with a piece of wire. One end to ground & move the other end across where the keyboard plugs in.Just watch the fan & if it starts or tries to start then your in luck.If they power up they will usually work off power button or G3 hot.This even works if the mag safe shows dim green.
I know it's not the proper way to fix your laptop,but at least you can use it,or see if everything else works.Good luck

 

[Papabear60]

Seems to me if pin 6 is 0V then pin 5 = the voltage divider of 470K/180K. In fact the schematic says Vgs = 7.3V @ 20V DCin (running on adapter) and Vgs = 4.74V @ 13V DCin (running on battery). So if pin 6 is 0V and pin 4 is 17V you should not be seeing 1V on pin 5. Probably more like 6.5V. Check those 2 resistors if you are sure teh FET is OK.

Dadioh, I think we are getting close to the issue as the resistors are fine but I read 7 ohms to GND at pin 3 of the FET which I believe is caused by Cap C6915 0.1uF BUT i can't locate it as it jumps to another part of the board! I can't locate U6915 either so I will have another go tomorrow in locating them but if anyone knows where they are located and can save me the hours it would be appreciated!

----------

Great!
Google RCLAMP2402B to find on-line suppliers or try Newark Electronics which was suggested to me earlier by cmdrdata?

 

[Dadioh]

Dadioh, I think we are getting close to the issue as the resistors are fine but I read 7 ohms to GND at pin 3 of the FET which I believe is caused by Cap C6915 0.1uF BUT i can't locate it as it jumps to another part of the board! I can't locate U6915 either so I will have another go tomorrow in locating them but if anyone knows where they are located and can save me the hours it would be appreciated!

----------

Great!
Google RCLAMP2402B to find on-line suppliers or try Newark Electronics which was suggested to me earlier by cmdrdata?

Going from memory I think that U6915 and Q6915 are located just above the ethernet magnetics towards the LVDS connector. I think Q6920 is there too.

 

[Dadioh]

Hey,I got a few macbooks that wouldn't power up from power button or the G3 hot.I get lucky with a piece of wire. One end to ground & move the other end across where the keyboard plugs in.Just watch the fan & if it starts or tries to start then your in luck.If they power up they will usually work off power button or G3 hot.This even works if the mag safe shows dim green.
I know it's not the proper way to fix your laptop,but at least you can use it,or see if everything else works.Good luck

Interesting. The power button passes through pin 5 of the keyboard connector. Is it always around pin 5 that you see this phenomenon?

So if it won't power off the keyboard power button but this method works it probably means a bad keyboard I assume. I had thought that the 2 pads that were shorted to start the machine were just the same circuit as the power button but looking at the schematic I'm not so sure now. So in that case there could be a circumstance where the 2 methods yield different results.

 

[peislander]

Thanks for your input - I have learnt a lot from your other inputs in the thread so thanks for chiming in here.

The schamtic I have is different as attached.

I have managed to replace the dual FET Q6910 but still does not power up.
I got the voltages from another Macbook unibody 13" that powers up but only through the SMC debug process as described in this thread whereas my Macbook pro will not power up either way.
So you are right in that these voltages could be wrong but my way of thinking was that this circuit is probably not the reason my other Macbook wont power up and therefore the voltages were probably good?

Interesting. The power button passes through pin 5 of the keyboard connector. Is it always around pin 5 that you see this phenomenon?

So if it won't power off the keyboard power button but this method works it probably means a bad keyboard I assume. I had thought that the 2 pads that were shorted to start the machine were just the same circuit as the power button but looking at the schematic I'm not so sure now. So in that case there could be a circumstance where the 2 methods yield different results.

I just got a late 2008 A1278 mobo on ebay with liquid damage.I cleaned it up & put it in a good case & tried power button & G3 hot jumper & still wouldn't power up.Tried jumper wire to ground & ran across where keyboard plugs in & it tried to start but didn't then I tried again while jumping the G3 hot & it booted & the magsafe turned from dim green to bright green & then orange to charge the battery.Now the only issue with this mobo is it always thinks its plugged in.It shows battery percent boots & works on battery.It also drains a good battery when just sitting off on the shelf.Thanks for any ideas

 

[cmdrdata]

Interesting. The power button passes through pin 5 of the keyboard connector. Is it always around pin 5 that you see this phenomenon?

So if it won't power off the keyboard power button but this method works it probably means a bad keyboard I assume. I had thought that the 2 pads that were shorted to start the machine were just the same circuit as the power button but looking at the schematic I'm not so sure now. So in that case there could be a circumstance where the 2 methods yield different results.

First, I want to say how much I appreciate Dadioh for starting this thread. I have learned a lot from y'all, and each posting sheds new light on how our Mac's worked and keeps my aging brain exercised.

This posting by peislander is interesting. I too thought that the power button on the keyboard ends up on the same printed circuit path. Good info fore the future.

One thing that is confusing the issue is the pair of Zener diodes on the SCA/SCL lines (RCLAMP2402B a 3 pin device) versus the dual FET package (6 pin device). In my opinion, the RCLAMP being missing as posted by destic is not a reason for the system not powering up. It is strictly a protective device to prevent the SCS/SCL lines from being subjected to static electricity when magsafe or battery is connected/disconnected (trigger/breakdown voltage around 40v), whereas the SDA/SCL lines are logic levels (around 3v pulses). For papabear's specific non-start issue, I think based on current symptoms, the focus should be on the dual FET voltages.

 

[Papabear60]

Going from memory I think that U6915 and Q6915 are located just above the ethernet magnetics towards the LVDS connector. I think Q6920 is there too.

Found it - thanks! It was just up from the led driver I was working on from your other thread - Who wooda thunked it
The cap was fine but pin 5 of Q6915 is at 7 ohms so I'm thinking thats next to be replaced.... Think we are getting there one step at a time

 

[Papabear60]

First, I want to say how much I appreciate Dadioh for starting this thread. I have learned a lot from y'all, and each posting sheds new light on how our Mac's worked and keeps my aging brain exercised.

This posting by peislander is interesting. I too thought that the power button on the keyboard ends up on the same printed circuit path. Good info fore the future.

One thing that is confusing the issue is the pair of Zener diodes on the SCA/SCL lines (RCLAMP2402B a 3 pin device) versus the dual FET package (6 pin device). In my opinion, the RCLAMP being missing as posted by destic is not a reason for the system not powering up. It is strictly a protective device to prevent the SCS/SCL lines from being subjected to static electricity when magsafe or battery is connected/disconnected (trigger/breakdown voltage around 40v), whereas the SDA/SCL lines are logic levels (around 3v pulses). For papabear's specific non-start issue, I think based on current symptoms, the focus should be on the dual FET voltages.

Good news after replacing the voltage comparator it now powers up on SMC bypass / debug mode but not through the power button or g3hot short. I tried peislander's running gnd across keyboard contacts and nothing. I also tried it with g3hot shorted and nothing BUT interestingly enough once you have powered up in SMC debug mode just shorting out g3hot powers the laptop up everytime. As soon as you remove ac adapter then nothing will power it up other than Dadioh's SMC debug mode.

My hunch is the trouble lies in the battery charging area as Dadioh's previous threads talked about the SMC, ac adapter and battery charging chip all talk to each other before the charger gives the green light so that is where I am going to start looking but I would be interested to find out from peislander if the Macbooks he successfully starts up running gnd across the keyboard connectors start in SMC bypass mode (i.e. high fans and no battery charging) or if they start up in normal mode ?

 

[peislander]

Good news after replacing the voltage comparator it now powers up on SMC bypass / debug mode but not through the power button or g3hot short. I tried peislander's running gnd across keyboard contacts and nothing. I also tried it with g3hot shorted and nothing BUT interestingly enough once you have powered up in SMC debug mode just shorting out g3hot powers the laptop up everytime. As soon as you remove ac adapter then nothing will power it up other than Dadioh's SMC debug mode.

My hunch is the trouble lies in the battery charging area as Dadioh's previous threads talked about the SMC, ac adapter and battery charging chip all talk to each other before the charger gives the green light so that is where I am going to start looking but I would be interested to find out from peislander if the Macbooks he successfully starts up running gnd across the keyboard connectors start in SMC bypass mode (i.e. high fans and no battery charging) or if they start up in normal mode ?

They mostly start normal & it depends on the mobo weather it will charge or not.I got some here that has no green light but will charge the battery slowly.I got one with green light that won't charge a battery.I got one here dim green that will only work off battery.I got one dim green that will only power up with a charged battery when plugged in.It will slowly charge the battery but won't power up with out a good battery.
Once I get them fired up they always work using the power button & fan at normal speed.
Have you been trying with or without a good battery?Is there power at the keyboard connector?Does the fan even try to move when your try grounding keyboard connector?Do you got 3.42 on G3 hot?
Hopefully we can help each other to get this figured out.Cheers

 

[Papabear60]

They mostly start normal & it depends on the mobo weather it will charge or not.I got some here that has no green light but will charge the battery slowly.I got one with green light that won't charge a battery.I got one here dim green that will only work off battery.I got one dim green that will only power up with a charged battery & will slowly charge the battery.
Once I get them fired up they always work using the power button & fan at normal speed.
Have you been trying with or without a good battery?Is there power at the keyboard connector?Does the fan even try to move when your try grounding keyboard connector?Do you got 3.42 on G3 hot?
Hopefully we can help each other to get this figured out.Cheers

Interesting as you literally have one of each case!

This one we have testeed with known good battery, ac adapter and magsafe connector.
G3HOT is good
Ac adapter shows no green or orange light but sometimes it does pulse orange
Works fine using Dadioh's SMC bypass.
Fan does hint at moving when I try your grounding of the keyboard connector but does not actually spin - A couple of times I thought it was going to spin as it "rocked" off its stationary position but it never did no matter how many times I tried it.

 

[peislander]

Interesting as you literally have one of each case!

This one we have testeed with known good battery, ac adapter and magsafe connector.
G3HOT is good
Ac adapter shows no green or orange light but sometimes it does pulse orange
Works fine using Dadioh's SMC bypass.
Fan does hint at moving when I try your grounding of the keyboard connector but does not actually spin - A couple of times I thought it was going to spin as it "rocked" off its stationary position but it never did no matter how many times I tried it.

Not all my mobo's needed the grounding trick.I kinda forget what ones I needed to ground on.I didn't know about the G3hot till I stumbled across this thread.When I got the mobo's I would wash them in a tuperware dish with iso in it & blow off with compressed air.If it didn't boot with power button I would try the grounding trick.The last one I got as mentioned in an earlier post needed the ground trick for sure & I didn't think it was gonna start but it started after quite a few tries.Good luck