SMC Issue on MBP 13 - Hardware Troubleshooting Guide

[Mac,Duh]

SMC SMBus Battery/Charger issues...

I have this issue on a unibody MacBook (A1342), but from reading this thread, this part of the circuitry is fairly similiar to the MBP, so I am trying this forum for some help. This thread in particular covers a lot of similiar circuitry so hopefully someone has seen similiar issues and can help.

I have several liquid damaged boards exhibiting this problem:

• The boards will not boot on battery because the SMBus for the battery/charger chip is not working.
  
• These boards WILL boot when a/c is connected and will pass all the ASD sensor tests, but (as expected), does not show any battery connected.
  
• An oscilloscope shows that the SMBus clock line from the SMC to the battery/charger is working as there are periodic series of clock pulses. However, the data line just stays high and obviously no devices respond.
  
• In cases where the clock and data line shows low impedance (< 1K or 0 ohms), I have removed or changed the U7000 charger chip (ISL6258 or ISL6259). In some cases, after removal, the clock and data lines are still around 10K in impedance. In other cases, they are around 50K. But in either case, even with removal of U7000, and in some cases, replacement, the SMBus data line still shows no activity even though the clock line is still going.

Normally, I would suspect a problem with the SMC chip data line, but the fact that I have so many boards that exhibit the same problem makes me suspect that I am missing something. Also, in one case, the SMBus was working, but in debugging other power supply issues, U7000 shorted out and upon replacement, the board now exhibits the same non-working data line problem.

Some other clues:

• A working board shows relatively high impedance on the SMBus clock and data lines (around 60K ohms), as well as on the regulated G3Hot line
  
• Most boards show about 10K ohms impedance on both the SMBus clock and data lines after removal of U7000. In most cases, the impedance of the regulated G3Hot is also about 12-18K, but there are some that are about 60K but still no SMBus data activity.
  
• Where U7000 was replaced, it is working and able to power the board and but cannot charge the battery since the SMC doesn't see the battery due to the SMBus issue

Has anyone experienced anything similiar? What could be causing the SMBus data line to be stuck high? The SMC is trying to clock data in and out, but the data is not showing up on the bus. There is nothing else on the SMBus other than the U7000 chip, the battery (known working), and 1K pull-up resistors (which check out fine).I find it hard to believe that the SMC data line is shot on all these boards. There is also the clue of low impedance on the regulated G3Hot line. Despite the low impedance, it show normal voltage when connected to the battery.

I have been chasing this issue for months and would welcome any insight from this knowledgeable group.

 

[rufunky]

I have a 2011 MBP 15" that has a problem with keyboard function. I have already replaced the keyboard, but it still acts like the shift key is stuck on. Any ideas on how to repair it. I am guessing it has something to do with the connector on the board J5713.

I had a problem similar to this, some of the keys just would not work.If this was a liquid damaged there are two things I would suggest ( if you haven't done so already ). Remove the keyboard flex ribbon take a tooth brush dipped in 90+ isopropyl alcohol, get the bristles of the brush inside the flex ribbon connector to remove any debris or corrosion. Also, take an eraser head to the flex ribbon pads.

 

[Dadioh]

I have a 2011 MBP 15" that has a problem with keyboard function. I have already replaced the keyboard, but it still acts like the shift key is stuck on. Any ideas on how to repair it. I am guessing it has something to do with the connector on the board J5713.

The shift key goes direct from the keyboard connector to the keyboard/trackpad chip I think. Check the traces and make sure there is no corrosion. I have replaced that keyboard device before but try cleaning the pins first.

 

[rufunky]

When do you say when?

When do you throw in the towel and start with a new board??

I have a severely abused MacBook 2011 that appears to have been left in an ultrasonic cleaning tank to long. Quite a few components are missing around the U7000. As you can see, the parts list is already adding up.

RESISTORS
R7051 2.2 ohm 5% 1/16 402
R7025 0 ohm 5% 1/16 402
R7022 10 ohm 5% 1/16 402
R7021 10 ohm 5% 1/16 402
R7013 1k 1% 1/16 402
R7002 100k 5% 1/16 402

CAPACITORS
C7050 1uf 10% 16v X5R 402
C7025 0.22uf 10% 10v CERM 402

I'm not sure about the rest of the board and am wondering if I should just start with a new non working logic board off ebay.

 

[paolo8721]

I am not aware of a Mac version of the board viewer (but am interested to hear of one).

You can use WineSkin in OSX with whatever boardviewer.exe (Landrex TestLink) that you already use - it's free and very light weight.

WineSkin

 

[rufunky]

Here is how a resistor divider works. Pin 3 gets it voltage from the two series resistors R7010 (30kohm) and R7011 (9.3kohm). Total resistance is 39.3kohm so 30kohm will drop the voltage by 30kohm/39.3kohm = 0.75. So 16V * 0.75 = 12V. Starting with 16V you lose 12V across R7010 leaving 16V - 12V = 4V.

You should have 4V on pin 3 if you have 16V at the top of R7010 and both resistors are correct. Of course, this assumes that U7000 pin 3 is a high resistance to ground so that it does not affect the resistor divider. If U7000 pin 3 has failed (and is a low resistance to ground) it can affect the divider and you will not get 4V even if both resistors are correct. In this case you must replace U7000.

OK, so I replaced both the R7011 9.31k Resistor and the U7000 IC. I plugged in the mag safe and still no green or orange light.

-I checked the resistance on R7011 with the U7000 installed and it now measures 10k ( I assume that's good ) where before I was not getting a reading.

-I also checked the voltage on Pin 3 of U7000 and it is now reading 5v ( thought it was supposed to be 4v? ) where before it was 0v.

-I checked pin 14 of U7000 and I am still getting 0v so nothing is coming out.

What should I try next??

 

[mac-n-sauce]

OK, so I replaced both the R7011 9.31k Resistor and the U7000 IC. I plugged in the mag safe and still no green or orange light.

-I checked the resistance on R7011 with the U7000 installed and it now measures 10k ( I assume that's good ) where before I was not getting a reading.

-I also checked the voltage on Pin 3 of U7000 and it is now reading 5v ( thought it was supposed to be 4v? ) where before it was 0v.

-I checked pin 14 of U7000 and I am still getting 0v so nothing is coming out.

What should I try next??

Generally at this point i get out my hammer!

 

[rufunky]

Generally at this point i get out my hammer!

lol tempting

 

[Dadioh]

OK, so I replaced both the R7011 9.31k Resistor and the U7000 IC. I plugged in the mag safe and still no green or orange light.

-I checked the resistance on R7011 with the U7000 installed and it now measures 10k ( I assume that's good ) where before I was not getting a reading.

-I also checked the voltage on Pin 3 of U7000 and it is now reading 5v ( thought it was supposed to be 4v? ) where before it was 0v.

-I checked pin 14 of U7000 and I am still getting 0v so nothing is coming out.

What should I try next??

I would double check the solder joints on U7000 to make sure they are all good. I have often had issues with a couple of bad joints that needed to be touched up. Very tricky soldering job on those QFN's.

 

[rufunky]

I would double check the solder joints on U7000 to make sure they are all good. I have often had issues with a couple of bad joints that needed to be touched up. Very tricky soldering job on those QFN's.

That's definitely possible. I will go over them when I get back to the shop. Is there anything else that would cause nothing to come out of pin 14 if I'm getting 4v in pin 3?

 

[Dadioh]

That's definitely possible. I will go over them when I get back to the shop. Is there anything else that would cause nothing to come out of pin 14 if I'm getting 4v in pin 3?

Lots of things. For it to put out 3V on pin 14 it has to be happy with all the sense lines and feedback loops. Are you getting 12.5v out of the charge circuit with battery disconnected?

 

[rufunky]

Lots of things. For it to put out 3V on pin 14 it has to be happy with all the sense lines and feedback loops. Are you getting 12.5v out of the charge circuit with battery disconnected?

I'm not sure I was running late and didn't test all the pins. Are you referring to pin 23?

 

[jpdo]

Hi,

My macbook now charges and turns on but with external monitor everything works fine, but with macbook display only appears white with some black stains, do you know what can be?.

Thanks

 

[rufunky]

Hi,

My macbook now charges and turns on but with external monitor everything works fine, but with macbook display only appears white with some black stains, do you know what can be?.

Thanks

If you had disassembled this macbook, check the LCD ribbon is in securely. But sounds like the screen its self has had physical damage and needs replacement.

 

[kricher]

I double the post from MBA thread. Mby here i can get help.


Hi there. So my keyboard was damaged. I replaced it by the second hand one from eBay. All working now, BUT NO KEYBOARD BACKLIGHT. I tryed to put backlight plastic from new one, and from old one. NO LIGHT. On motherboard connector of keyboard backlight is 1V. I tryed to do the SMC reset also. So im writing here as a last chance to get it work again. Thanks.

Is it possible to give a power straight to backlight plastic connector to be shure that it works? should be a 5V there i think.

 

[mac-n-sauce]

Might sound silly, but have you tried turning it up with the keyboard?(F5,F6) on 2009 and above models. Sometimes when I have changed mine out they reset to off and no light will show at all.

 

[jpdo]

just a question what is isense in logicboard of macbook?

 

[Dadioh]

just a question what is isense in logicboard of macbook?

In electronics "I" = current. So isense would be a current sensor measuring how much current a device is drawing. And if you multiply the voltage X current you get the power that device is consuming.

 

[jpdo]

In electronics "I" = current. So isense would be a current sensor measuring how much current a device is drawing. And if you multiply the voltage X current you get the power that device is consuming.

Thanks, just another question.
My macbook have a white screen with some stains using this display but when connected to a external display works fine. Can be the lvds cable?

Thanks

 

[rufunky]

Lots of things. For it to put out 3V on pin 14 it has to be happy with all the sense lines and feedback loops. Are you getting 12.5v out of the charge circuit with battery disconnected?

Ok, here we go again. After U7000 replacement with just charger plugged in no battery. ( mind you, I believe all U7000 pads are making contact on the bottom even though some of the solder joints don't seem to travel up the side of the chip. I had to order a smaller tip for my solder iron because mine just doesn't fit in there well. All of the solder points are perfectly lined up as I angled them under the scope to check.

Pin 1 - 0V - CHGR_AGATE - Turns on FET to allow DC-in to appear at charger FETS =15.6v
Pin 2 - 16V - CHGR_DCIN - From magsafe (anywhere from 16 to 18.5V) =16.8v
Pin 3 - 4V - ACIN - Resistor divider 30K/9.31K (DCIN / 4) = .005v
Pin 14 - 3.3V - ACOK - Signal to SMC that charger is happy. = .0v
Pin 17/18 - 12.5V - CSOP/CSON - Measured across sense resistor to/from battery = .195v
Pin 19/20 - 5V - VDD/VDDP - internally generated 5V supply =5.08v
Pin 23 - 12.5V - CHGR_PHASE - Output of charger = .17v
Pin 27/28 - 16V - CSIP/CSIN - Current Feedback from sense resistor feeding FETS = 0v

Seems like my the results are all over the charts here. What should I test next??

 

[Phantom Gremlin]

All of the solder points are perfectly lined up as I angled them under the scope to check.
...
Seems like my the results are all over the charts here. What should I test next??

Are your voltage readings from a multimeter?

At some point you will probably need to use an oscilloscope to observe some of these pins. I'm not familiar with this circuitry, but you might not be dealing with purely DC stuff.

You did use the word "scope", but perhaps as an abbreviation for "stereo microscope", rather than "oscilloscope".

Sorry I haven't kept up with this entire tread very carefully. Perhaps you have already discussed this.

 

[jpdo]

To test the logic board components i need to run the apple hardware test in extended mode?

Thanks a lot.

 

[rufunky]

Are your voltage readings from a multimeter?

At some point you will probably need to use an oscilloscope to observe some of these pins. I'm not familiar with this circuitry, but you might not be dealing with purely DC stuff.

You did use the word "scope", but perhaps as an abbreviation for "stereo microscope", rather than "oscilloscope".

Sorry I haven't kept up with this entire tread very carefully. Perhaps you have already discussed this.

Hi Phantom, Yes my readings are from a multimeter. I'm pretty new to this, I've heard of an oscilloscope but do not have one nor would I know how to use one :/. Sorry, I was referring to a stereo microscope and should have made that more clear.

 

[jpdo]

hi.
Now my keyboard isn't working fine.
The 'P' Key and caps Lock Key doesnt work. And the AHT says that dont have any problem with logic board.

Anyone can help-me? What i need to check?

Another Problem is the display, i replace the lvds cable and continues with backlight but no picture, can be the component that i have missing?

Thanks

 

[priitv8]

...I've heard of an oscilloscope but do not have one nor would I know how to use one :/.

You can get a good start from Velleman here:
LEARN HOW TO GET THE MOST OUT OF YOUR DIGITAL OSCILLOSCOPE
PS they also make a nice and cheap scope HPS140i that should get you started.