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SMC Issue on MBP 13 - Hardware Troubleshooting Guide
- Thread starter Dadioh
- Start date
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Hi Dadioh,
Thanks for replying and taking a look here is the pic. The part is gone just solder left behind now. As I said I think it was a resistor higher wattage than normal(bigger) for smt device. I think possibly batt charge current flows thru it??
D
OK. I will have a look on one of my boards at home and let you know what I find.
Macbook Air unibody A1370 late 2010
Hi,
First of all, thank you all for this thread and for your contribution to the "community" of those who refuse to believe that something can be too complicated to repair. I believe this thread is one of a kind because no matter how much or how cleverly I tried to google there was no information that I could find regarding logic board level troubleshooting or repair.
Secondly, as I'm not a native english speaker, please excuse me my mistakes.
Well, here's my story.
Couple of months ago I bought a water-damaged (actually it was soup) MBA A1370 late 2010 model laptop from a guy who claimed that in Apple service they wanted to replace the logic board for 600 euros. It was too expensive, so he sold it.
I disassembled it , cleaned all parts with isopropyl alcohol as thoroughly as I could, except for the topcase with keyboard layers because there's no way to disassemble those on MBA late 2010. I just submerged the topcase (without lcd of course) into isopropyl and hoped it would dissolve any residues of soup.
So, after drying i assembled the laptop and connected power cable which turned into amber...But only for minute or two, then it turned to green. After disconnecting the cable and reconnecting it turned to amber again, then to green and never turned to amber again when i disconnected and reconnected the cable. The computer itself didn't respond to power button presses. Tried SMC reset and every other trick but without luck.
So I disassembled it again and started to troubleshoot. I tested voltages on battery connector pins and the maximum reading my multimeter gave was something like 0,5V. Battery has couple of those stickers that indicate contact with liquids, one of those was red. So I concluded the battery was dead.
In order to test the logic board I managed to purchase schematics along with boardview files. I also purchased known good logic board from eBay.
After reading this thread I tried to do SMC_ON_OFF_L with old logic board installed but without any success. However the computer booted up (shorting smc on off pads on logic board) when new logic board was installed. Everything works perfectly with new logic board except for the keyboard...All the keys work..there's a lag sometimes or you have to press keys twice but they work...Unfortunately the only key that doesn't work is power button...So to power the computer up I need to short SMC ON OFF pads on logic board.
I took my time and put two logic boards side by side, read schematics and started to measure and compare the voltages on points where I thought it would be logical for such errors to occur.
The board was live and I found that DC in board is completely OK...also it seems that G3Hot is OK.
First difference I found was the voltage difference on R6905. On good board it read 14,4V and on bad board it read 14,9V. It seemed strange, so I read the schematics and dig along the path where the current would come and to my surprise I found that R7080 was completely missing on bad board. It's the resistor that's close to the power FET's Q7080 and Q7085..That part of the schematics is responsible for PBus Supply and Battery Charger (please see attached files).
So my concern is if the missing R7080 could the board not to boot up. It's the 100kohm 0201 resistor and I'm still looking for the place where to purchase it from. Also I'm worried that I might not be able to solder it with my soldering iron. It takes a while until I can replace the missing resistor. Meanwhile I'd like to search for more erros.
Please, any useful information or ideas are very appreciated.
Attached are the schematics and boardview files.
http://www.4shared.com/zip/Z6xHsfRe/MacBook-Air-A1370-820-2796-K99.html
Hi,
First of all, thank you all for this thread and for your contribution to the "community" of those who refuse to believe that something can be too complicated to repair. I believe this thread is one of a kind because no matter how much or how cleverly I tried to google there was no information that I could find regarding logic board level troubleshooting or repair.
Secondly, as I'm not a native english speaker, please excuse me my mistakes.
Well, here's my story.
Couple of months ago I bought a water-damaged (actually it was soup) MBA A1370 late 2010 model laptop from a guy who claimed that in Apple service they wanted to replace the logic board for 600 euros. It was too expensive, so he sold it.
I disassembled it , cleaned all parts with isopropyl alcohol as thoroughly as I could, except for the topcase with keyboard layers because there's no way to disassemble those on MBA late 2010. I just submerged the topcase (without lcd of course) into isopropyl and hoped it would dissolve any residues of soup.
So, after drying i assembled the laptop and connected power cable which turned into amber...But only for minute or two, then it turned to green. After disconnecting the cable and reconnecting it turned to amber again, then to green and never turned to amber again when i disconnected and reconnected the cable. The computer itself didn't respond to power button presses. Tried SMC reset and every other trick but without luck.
So I disassembled it again and started to troubleshoot. I tested voltages on battery connector pins and the maximum reading my multimeter gave was something like 0,5V. Battery has couple of those stickers that indicate contact with liquids, one of those was red. So I concluded the battery was dead.
In order to test the logic board I managed to purchase schematics along with boardview files. I also purchased known good logic board from eBay.
After reading this thread I tried to do SMC_ON_OFF_L with old logic board installed but without any success. However the computer booted up (shorting smc on off pads on logic board) when new logic board was installed. Everything works perfectly with new logic board except for the keyboard...All the keys work..there's a lag sometimes or you have to press keys twice but they work...Unfortunately the only key that doesn't work is power button...So to power the computer up I need to short SMC ON OFF pads on logic board.
I took my time and put two logic boards side by side, read schematics and started to measure and compare the voltages on points where I thought it would be logical for such errors to occur.
The board was live and I found that DC in board is completely OK...also it seems that G3Hot is OK.
First difference I found was the voltage difference on R6905. On good board it read 14,4V and on bad board it read 14,9V. It seemed strange, so I read the schematics and dig along the path where the current would come and to my surprise I found that R7080 was completely missing on bad board. It's the resistor that's close to the power FET's Q7080 and Q7085..That part of the schematics is responsible for PBus Supply and Battery Charger (please see attached files).
So my concern is if the missing R7080 could the board not to boot up. It's the 100kohm 0201 resistor and I'm still looking for the place where to purchase it from. Also I'm worried that I might not be able to solder it with my soldering iron. It takes a while until I can replace the missing resistor. Meanwhile I'd like to search for more erros.
Please, any useful information or ideas are very appreciated.
Attached are the schematics and boardview files.
http://www.4shared.com/zip/Z6xHsfRe/MacBook-Air-A1370-820-2796-K99.html
Hi cvppb,
I too am grateful for this thread, I'm surprised it's just a thread "hanging by a thread" as it seems there's a lot of interest in Apple repairs before being ripped off by Apple just replacing major assembly's.
Have you tried digikey.com or jameco.com they both sell SMT components. Are you sure that it's actually missing and not a production run change? As for the keyboard sounds like another bath might be in order, but just the keybd I wouldn't subject a working logic card to more stress. And I wouldn't write the battery off yet, unless you can see where the liquid actually got into the batt, the red dot shows it was on the outside of the battery.
I too have a MBA 11 I picked up, mine was spilled milk. I have washed the logic card separately in an alcohol bath. I've only been able to get it to power on and charge the batt, and most recently I was able to get it tp power on but it won't pass post and boot. The SMC reset works fine. It only comes on and the CPU and GPU get warm with the fan slowly increasing to max speed. Something's keeping the clock from running or something. But I can now check your schematics for some points to check.
Where did you get the schematics? I have a MB 13 I may need to look up a resistor that melted in the charging circuit. Dadioh was was going to see if he could see what it was on a good board for me.
Hi,
I'm certain the resistor is actually missing, because under the magnifying glass I can see the points where it was soldered to. Maybe I ripped it off during cleaning process while I was brushing the board with toothbrush.
For the keyboard I planned another cleaning, but this time using ultrasonic cleaning device with heater. There are some service shops in my city that offer the service for reasonable price. I've heard that in some cases it's more effective way of cleaning than alcohol bath. In my case, I found that isopropyl was rather weak solvent for the residues of this specific dried up liquid (soup). So as I can't clean keyboard layer by layer, maybe heat and ultrasound will do the trick.
I'm not sure how can I test my battery..Once it's completely depleted what should be the residual voltage? I could test it with my good logic board and see ifi It gets charged but I'm afraid that if the battery has shortages in it's inner circuit it could ruin something on my good logic board as well. I can't find the place where the liquid could get into the battery though, but battery connector
was corroded for sure before I started cleaning.
Thanks for the links...I found proper resistor in no time.
I purchased schematics from http://laptop-schematics.com/view/8355/
It seems that all Apple's unibody laptops have pretty similar schematics, but the actual layout on board is different.
The ultrasonic cleaning should do well on the keyboard assembly. Just make sure that it has dried up completely before powering it up and trying to use it. I've done this on a logic board with no problem.
On the battery problem: It is unlikely that fluid gets into the internal part of the battery pack to damage it. Most likely problem is that the protection circuitry inside the battery pack senses an over current and it then turned off the output as a self protection. On a normal usage this pack would have around 12.6v full charge and would be around 9v when depleted. The protection circuit would not allow the batteries to discharge to below 3v per cell. In your schematic R6950 (a 10kOhm resistor) provides a SYS_DETECT signal to the pack to enable its output. So measuring the pack V+ terminal while disconnected from the logic board breaks this connection and the pack V+ output will be ~0v.
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Thank You.
Indeed...I pried the battery pack open and found no traces of liquid inside. Also measured around 3V on every cell (cell's nominal is 3,75). But it's dead...No output and it doesn't matter if it's connected to logic board or not. R6950 is OK.
I believe there is no reasonable way to wake the battery up from it's shutdown mode.
When the battery is in-place/connected and the magsafe connected, what voltage did you see/measure between pins 1/2/3 and 7/8/9? Also with this setup, when you press the battery charge test button, did you see any charge status LED light up? Also what do you get when you check: "About This Mac->More Info->System Report(if OSX Lion)-> Power"?
Here's some info regarding generic "smart" Li-Ion battery pack:
Why won't my battery power my portable electronic device? It has worked before, but now I can't get my battery to output any power.
...battery pack has built-in circuit protection to ensure safe operation and reliable performance. Any number of things may trigger this circuit protection, and thus the battery pack must be reset in order to restore the voltage output. The circuit protection can be triggered by the following:
1. Adjusting the output voltage when connected to a device.
2. Disconnecting the battery pack and then reconnecting to a device that is turned on.
3. Leaving the DC output cable connected to the battery and then accidentally short circuiting the terminals on the DC output cable by coming into contact with keys or other cabling in a laptop bag etc.
To reset the battery pack and restore the voltage output:
By connecting any external battery pack to its AC charger, the battery pack will sometimes reset itself after being connected to the AC charger for a number of seconds.
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Hi Dadioh,
Thanks for replying and taking a look here is the pic. The part is gone just solder left behind now. As I said I think it was a resistor higher wattage than normal(bigger) for smt device. I think possibly batt charge current flows thru it??
D
Sorry this took so long but I had a look this morning and this device is a ferrite bead. Ferrites are used as EMI filter devices. Your particular ferrite bead is on the ground side. There is an identical one on the positive battery side. If you can find a replacement the best solution is to replace it with a ferrite. If you can not find a replacement you "could" just short across it at risk of higher EMI emissions from the Macbook. It may be required to meet the FCC emissions requirements but you may find it is OK.
The bigger question is.... why did it evaporate in the first place? Seems like there was a whack of current flowing through the battery and that happened to be the weakest point. Be careful when powering up after replacing it in case the fault condtition still exists. The fault could be on the logic board or on the battery itself.
Attachments
After disconnecting and reconnecting battery connector while magsafe was connected the battery sort of "woke up"...
Now it's showing:
6,8V on pins 1-3;
3,4V on pins 4-5;
0V on pins 6-9
Before that it showed around 1V on pins 1-3 and 3,4V on 4-5
There's no battery charge test button on macbook air late 2010.
System information claims: no battery
If battery is not connected, the charging circuit gives output of 8,4V
If connected it drops to 6,4V.
If I disconnect lcd cable and power it up with magsafe connected (vent starts ) then it stays powered up even if I disconnect magsafe. If there are consumers like lcd connected it stops running the same moment I disconnect magsafe.
It won't power up from battery no matter what and the battery is not charging.
I think that battery's protection circuit is damaged because logic board and dc-in came from working laptop..There's nothing else that can cause errors in my opinion.
Thanks a lot for Your help!
OK, It seemed that your battery is depleted, normal discharged state. I don't have an MBA so I don't know the PPBUS_G3H voltage in normal condition (this is the load side of fuse F7040, page 50). In an MBP, this is nominally 12v. in an MBA Apple may use 2 cell Li_Ion configuration, thus 8.4v sounds correct if that is the case. I think if you let the battery charged in the system, the 6.4v reading you have will eventually get to 8.4v and it will then be able to power the system on battery power. Magsafe should be off then green in a few seconds then yellow/orange while the battery is charging, and green again when the battery is fully charged.
Separately when you do system info and it reported "no battery", that is caused by the CPU unable to get battery status that it normally get from the SDA/SCL lines (called I2C bus). See the papabear/pappabear2 thread in this same forum. These lines should be at G3HOT level (3.42v) under when all connected devices are idle because the SDA line is pulsed by the source (pulled to logic high by a resistor and driven to logic low when the device is sending signals).Pappabear had these pull-up resistors burned up and thus the CPU cannot see the toggling signal. SCL is clock line synchronous to the data transmission.
If you look at page 50 of your schematic, if you power the system from magsafe, fuse F7040 is the system load and power can come to it from magsafe or battery, and on the input side of that fuse there is a single FET that gates charging current to the battery. If this FET is turned on, battery power should flow thru the system, if it has sufficient charge.
I did a little googling and found out that newer MBAs battery has a voltage that is twice the Li-Ion cell voltage thus a fully charged MBA battery should be around 8.5v.
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Thanks Didioh that was the info I needed. I was able to find an axial lead bead in my junk box that fit more or less, very tight in there but it worked. My old battery charges up just fine now, just won't pwr MB for long. The new battery (non Apple) is apparently shorted and when I left it in for about 5 min that's what cooked my ferrite bead. Guess I'll be returning that! Go figure I would have thought a charger would be short ckt protected. Also thanks for the link that I'm sure will come in handy.
Thanks Didioh that was the info I needed. I was able to find an axial lead bead in my junk box that fit more or less, very tight in there but it worked. My old battery charges up just fine now, just won't pwr MB for long. The new battery (non Apple) is apparently shorted and when I left it in for about 5 min that's what cooked my ferrite bead. Guess I'll be returning that! Go figure I would have thought a charger would be short ckt protected. Also thanks for the link that I'm sure will come in handy.
Not sure who this didioh guy is... but I feel I can speak for him
Glad it worked out for you.
i have a problem the picture that i have circle has completly blew to the point where you can soldier a new chip in there anything i can do to get it back up and working again? The macbook turns on i can hear the cd drive running but no chime, no display. Although it does still charges.
The part number is for an N-channel power FET, however, I don't know which model Macbook it is, so without that info it would be hard to figure out what it does/control. Here's a diagram of that IC:
Attachments
Its off a mid 2010 13.3 macbook pro. Is there anything i can do to get it back up and running again as that chip litereally blew and is not replaceable since it damaged the board
If the board is damaged, I think the only recourse is get an identical/similar used logic board from eBay or elsewhere. I do not have a schematic for mid 2010 MBP, thus I cannot tell what that chip does. From your description, I'd guess that it is one of the high current low voltage output driver (1.x, 3v, or 5v regulated output supply). What was the cause of this failure? The picture seemed to indicate there was liquid spot just to the left of R560 blob (that big component to the right of the red circle).
That board is not mine. My boards had light liquid damaged and has only damage to the once chip that is circled. I guess one drop is all it took to make massive damages. I guess i'll buy a liguid damage board and swap these components over thanks!
In that case if I were you I'd clean the board up with isopropyl alcohol real well, and allow it to dry a few days while you order the K0365. I think digikey.com would have that available. It would be well worth the cost of trying. A logicboard, even bad ones may cost $100.
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I dont think thats possible because the pad for the chip is blown off the board making it unsolderable
I dont think thats possible because the pad for the chip is blown off the board making it unsolderable
In that case if you can figure out where the other end of the connection is then you can replace the track with wire and attach the new FET to the end points with wire.
I dont think thats possible because the pad for the chip is blown off the board making it unsolderable
Actually this is not as impossible as you think. This MOSFET has pins 5/6/7/8 tied together internally, and pins 1/2/3 similarly (for current carrying capacity), and pin 4 being the control/gate signal. Thus if you do as the picture below you are in effect recreating the existing connectivity. Since you have your friend's logic board you can perhaps determine where the 3 lines are supposed to go.
PS: Just to be careful, the picture below is showing pin1 where the dot is, and it is showing "top view". The previous image I posted where pin 4 is shown in the bottom left is the "bottom view".
Attachments
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I know i can get 1-4 pin solder down but as far as 5-8 there are gone all i see is copper and its really hard to track where they go
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I wish i had a really good camera so i can show yall but do yall think this is a good canadate to repair this board http://www.ebay.com/itm/MacBook-Pro...774568356?pt=Motherboards&hash=item27c2f51da4 or this http://www.ebay.com/itm/2010-Macboo...837681062?pt=Motherboards&hash=item4ab36a7fa6
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I wish i had a really good camera so i can show yall but do yall think this is a good canadate to repair this board http://www.ebay.com/itm/MacBook-Pro...774568356?pt=Motherboards&hash=item27c2f51da4 or this http://www.ebay.com/itm/2010-Macboo...837681062?pt=Motherboards&hash=item4ab36a7fa6
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I looked up my LATE 2009 unibody MBP schematic and there are two devices that looked similar to K0365, pinout wise. The one that blew up is most likely the FireWire output voltage MOSFET (notice the proximity to the firewire port. So I think the circuit wiring would be very similar. The other one is the ODD (optical disk drive) power supply.
Because of liquid infiltration, the firewire fuse wasn't able to protect it.
