Thanks for the information. I suppose this will be my next step after I get more familiar with the basics of testing MacBook logic boards.
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SMC Issue on MBP 13 - Hardware Troubleshooting Guide
- Thread starter Dadioh
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Thanks for the information. I suppose this will be my next step after I get more familiar with the basics of testing MacBook logic boards.
Hello and thanks Dadioh for this amazing, informative thread. Much learning for lots over my head at this point.
I'm trying to revive an eBay liquid damaged 13 inch mid 2010 MBP A1278 MC375LL/A. It won't start up at all. Both the magSafe that came with it and a known good magSafe go immediately to blinking green. I've removed, cleaned (isopropyl alcohol 91%) and put it all back together. Most of the damage was on the underside of the board. I cleaned and reapplied a thin layer of arctic silver on the processors. After reading the first fifteen pages of this thread and knowing I'm way out of my "comfort zone," I tried the temporary bypass = no response at all. I located the G3Hot on my board and tried that again getting no response. After trying and failing to read an old analog multimeter, I got a digital one.
The voltage on one G3Hot was 0 and on the other it was 3.37V. Must it be exactly 3.425V? These readings are without the battery in (will not charge); it only sends quick blinking on first one from the battery sensor.
I get 12.57V on both ends of the small white fuse near battery connector with the magSafe plugged in.
I also tried a wire grounded to screw and touching 5th keyboard connector location and got no response from the fan. After studying some of the photos posted I realize my board may have other problems. Can you please also tell me if me and my board are cooked and out of luck by looking at the circled areas on the photos. Are they burned places? Those areas on other photos are white/silver and mine appears burnt?
If all is not lost at this point what should I be testing next? I realize I need to get tiny leads for my multimeter, so on hold till then unless it's one of the bigger tests spots.
I ordered a new DC inboard from eBay hoping that will get the battery to charge; so I will be removing the logic board again. Getting that backlight cable back in securely was a real PITA.
Any directions greatly appreciated.
I'm trying to revive an eBay liquid damaged 13 inch mid 2010 MBP A1278 MC375LL/A. It won't start up at all. Both the magSafe that came with it and a known good magSafe go immediately to blinking green. I've removed, cleaned (isopropyl alcohol 91%) and put it all back together. Most of the damage was on the underside of the board. I cleaned and reapplied a thin layer of arctic silver on the processors. After reading the first fifteen pages of this thread and knowing I'm way out of my "comfort zone," I tried the temporary bypass = no response at all. I located the G3Hot on my board and tried that again getting no response. After trying and failing to read an old analog multimeter, I got a digital one.
The voltage on one G3Hot was 0 and on the other it was 3.37V. Must it be exactly 3.425V? These readings are without the battery in (will not charge); it only sends quick blinking on first one from the battery sensor.
I get 12.57V on both ends of the small white fuse near battery connector with the magSafe plugged in.
I also tried a wire grounded to screw and touching 5th keyboard connector location and got no response from the fan. After studying some of the photos posted I realize my board may have other problems. Can you please also tell me if me and my board are cooked and out of luck by looking at the circled areas on the photos. Are they burned places? Those areas on other photos are white/silver and mine appears burnt?
If all is not lost at this point what should I be testing next? I realize I need to get tiny leads for my multimeter, so on hold till then unless it's one of the bigger tests spots.
I ordered a new DC inboard from eBay hoping that will get the battery to charge; so I will be removing the logic board again. Getting that backlight cable back in securely was a real PITA.
Any directions greatly appreciated.
Attachments
A1278 820-2879-B mid 2010
So I'm still trying to figure out how to follow the complete power cicuit. Seeing I'm getting no G3hot I checked the R6905 . I am getting 16.8 on top and 0.02 on bottom. This is I believe a 1ohm resistor so what does that mean should be coming out bottom side?
Also, my schematics show a c5101 capacitor right next to R6905 yet my board does not have one. Again, I am going off of a A1278 820-2879 schematics and my board is a A1278 820-2879-B which is known to have a few differences when compared to the non B version. So I need to know if the c5101 capacitor fell off my board at some point.
So I'm still trying to figure out how to follow the complete power cicuit. Seeing I'm getting no G3hot I checked the R6905 . I am getting 16.8 on top and 0.02 on bottom. This is I believe a 1ohm resistor so what does that mean should be coming out bottom side?
Also, my schematics show a c5101 capacitor right next to R6905 yet my board does not have one. Again, I am going off of a A1278 820-2879 schematics and my board is a A1278 820-2879-B which is known to have a few differences when compared to the non B version. So I need to know if the c5101 capacitor fell off my board at some point.
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The spots circled are of no consequence. They are empty pad sites.
The fact that you have the 3.37v on the G3HOT is a good sign, does not have to be exactly 3.42v. The other point is a ground point so 0v is fine.
The quick blinking on the battery indicator generally means a dead battery. Could have been damaged by the liquid.
It sounds like your magsafe board is ok based on the readings you are getting.
Try unplugging the battery and see if it effects your light on your charger.
Are you sure about the C5101 Capacitor? That is part of the EFI Debug ROM circuit, not the G3HOT circuit.
Yes, I am sure there are two pads but no cap. I'm not sure if it is a difference in the revision of the board though.
Any idea what the voltage should be coming out of R6905?
Attachments
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your DC IN voltage. 16.5-18.5
i am working on the same board as you and mine is not there either.
I have checked with my schematic supplier and they do not have the revision b
EDIT:
Are you saying the top and bottom of R6905 should be 16.5- 18.5?
C5101 Capacitor is also missing on your board??
Bummer about the schematics. I have looked as well. I actually wouldn't mind paying for it but it is no where to be found. :/
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The cap is not there on mine and appears to have never been there. I had light liquid damage and am not missing any parts. I have no G3HOT at all
You should have pretty much the same voltage on both sides of that resistor it is only 1 ohm
I have had in the past the U6990 get blown.
I am still working on my U7000. Do not have good numbers there. similar to yours. Need to replace it. just haven't had time and was waiting on some smaller soldering tips
I figured I should be getting about the same bottom side. I'm going to pull the resistor tomorrow so I can more accurately test its resistance.
Nope, I replaced u7000 and my numbers are still off. Even weirde, now I'm getting high voltage on pin one. Dadioh said pin 1 should be 0. I am also waiting for a smaller tip and solder to go over the pins.
All my current U7000 PIN VOLTAGES are listed on the page before this one.
Yes, that's what he's saying.
If indeed that is a 1 ohm resistor like you previously said, the voltage on both sides of the resistor must be very nearly the same. Otherwise the resistor will burn up.
You'll need to learn a little more about electronics. Here's what you need to know about that resistor:
https://en.wikipedia.org/wiki/Ohm's_law#Circuit_analysis
I = V/R
So if the voltage across your resistor is (16.8 - 0.02) = 16.78V, then the current flow thru it will be
I = 16.78 / 1 or 16.78 amps.
Which brings us to power being dissipated in that resistor.
https://en.wikipedia.org/wiki/Electric_power#Definition
P = IV
P = 16.78 * 16.78
P = 281 watts
That's not possible. Not only is there no power adapter that can deliver that much power to your laptop, but also a tiny resistor will burn up at about 0.1 watts. There's no way it can survive with 16 volts across it for more than a few milliseconds.
Either that resistor has already destroyed itself or it's not really a 1 ohm resistor. It must be orders of magnitude higher in resistance.
Take this as an opportunity to study up on basic electronics. Have fun.
Thanks mac-n-sauce. I'm so glad to know I've still got a good chance here. With battery removed, and the battery indicator cable connected or disconnected the magsafe remains the same just blinking green.
Is the mid 2010 capable of starting up without some charge on battery? Maybe I should jump for a new battery?
Thanks for that explanation. I will read through the links you have provided. I briefly read about Ohm's law but it didn't make much sense to me ( I was never very good at math ) I know I have a lot to learn but I'm willing to put in the time to acquire the knowledge
Yes it can start without the battery but with a good magsafe.
You obviously have similar issues to myself and rufunky. Read some of the posts to chase down whats next. You do not need the battery at this point. Since you do not know if its any good anyway.
Just an update on my 2011 15" macbook pro:
Thanks Rufunky for a simple reminder of the basics.
I cleaned the flex ribbon again as suggested and wouldn't you know the keyboard is now fully functional.
Sometimes it just takes going back to the basics.
Waiting on a new wifi cable(suggested by Dadioh) and I have another resurrected Macbook Pro.
This one was easier than most.
Thanks to all who contribute!
Awesome! Yeah, I had this happen to me a couple times. Due to the location of the ribbon and connector in relation to the keyboard the spill almost always rolls off the keyboard onto this area.
I'm waiting on some caps and resistors from digikey for two of my boards. 40 parts in all ( bought 5 of each ) under $5 shipped. Not to many things you can get 40 of shipped for that price.
Thank you. Ok onward, after removing the logic board, and carefully inspecting the heat sink side, I think I've spotted a melted resistor? What is that in the first photo from ifixit? The second photo is my board where the same appears flattened and unreadable. The location is under the removed speaker.
Attachments
MBP 13" with constant fan and 90% cpu usage.
Hi there,
This is my first post so i am sorry if it's a wrong move to post it under this thread.
I have got MBP 13" 2010 with some problems listed below.
-Loud fan noise right after power up.
-Extremely slow os x lion freshly installed in 8 hours into a new hard disk. No other software installed on this laptop.
-A very high cpu usage at about 89 to 91% by System.
-Trackpad and keyboard does not seem to work.
-Battery quickly dies after unplugging from magsafe.
I thought first to replace the thermal paste and clean the fans and heatsink.
I did that and managed to get heat at about 40c. Now I am stuck with this high cpu usage which does not let me use the MBP.
I also did the SMC reset but no changes with either loud fans and high cpu usage.
Is there any relation netween faulty keyboard/trackpad and high cpu usage right at the startup.
Thanks
Hi there,
This is my first post so i am sorry if it's a wrong move to post it under this thread.
I have got MBP 13" 2010 with some problems listed below.
-Loud fan noise right after power up.
-Extremely slow os x lion freshly installed in 8 hours into a new hard disk. No other software installed on this laptop.
-A very high cpu usage at about 89 to 91% by System.
-Trackpad and keyboard does not seem to work.
-Battery quickly dies after unplugging from magsafe.
I thought first to replace the thermal paste and clean the fans and heatsink.
I did that and managed to get heat at about 40c. Now I am stuck with this high cpu usage which does not let me use the MBP.
I also did the SMC reset but no changes with either loud fans and high cpu usage.
Is there any relation netween faulty keyboard/trackpad and high cpu usage right at the startup.
Thanks
additions to my previous post
i think it's helpful to add this to the previous post that in activity monitor the "kernel_task" works at %200 cpu usage and all other processes are just like either 0 or 0.x values.
I also installed another battery under the bottom lid today but nothing has changed.
Also since I updated the os x lion (which took 7 hours roughly) the system started to use %98 of the cpu.
I am begging for help as this laptop out of warranty.
Regards
i think it's helpful to add this to the previous post that in activity monitor the "kernel_task" works at %200 cpu usage and all other processes are just like either 0 or 0.x values.
I also installed another battery under the bottom lid today but nothing has changed.
Also since I updated the os x lion (which took 7 hours roughly) the system started to use %98 of the cpu.
I am begging for help as this laptop out of warranty.
Regards
Bad Hard drive. Should take about 45min for OS install
Keyboard can have odd effects on the computer, but should not slow install process. Why is keyboard and track pad bad? Sounds like liquid damage.
thanks mac-n sauce Even though i couldn't find any traces of liquid damage on both keyboard and trackpad, i believe these parts had this experience.
The hard disk is taken from a working environment and i am sure there is nothing wrong with it. Also I can tell that system shouldn't be so slow responding even though hard drive is bad. Mouse moves slow, icons on he screen jumps up and down extremely slow, i think due to insufficient space in the cpu.
It's clear that an unknown process is eating up all the cpu resources and leaves me just 2 or 3% of cpu usage.
Laptop has been freshly installed.
Last night i lost my all hope about the laptop and listed in ebay uk.
i still have about a week to resolve this matter and expecting some help from an experienced guys like you out there.
If I can reduce the kernel task cpu usage to normal levels I am confident that i can replace both palmrest and keyboard.
Thank you. Ok onward, after removing the logic board, and carefully inspecting the heat sink side, I think I've spotted a melted resistor? What is that in the first photo from ifixit? The second photo is my board where the same appears flattened and unreadable. The location is under the removed speaker.
That is a current sensing resistor. If yours melted then it means it was carrying far too much current which would indicate a short further down stream.
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I have had this sort of behavior when there are bad sensors. You get a kernel task that chews up all the resources. High fan speed is another clue that the SMC doesn't like one of the sensors. I would run Apple Hardware Test and report back on which sensor fails.
Macbook pro mid 2010 ( 820-2879-b ) symptoms:
This has been fixed by replacing R6905
I'm working on figuring out why I am getting voltage on pin 1 of U7000. I traced back to R7085 (470k resistor) and on a known working I get 16.87v left side and 6.89v right side the one I am currently trying to fix is 16.66v left side and 15.91v right side. I tested the resistance while still mounted to the board and I am getting 470k which is correct. Is my multimeter wrong? or is there another reason that the voltage is making it through to the other side of R7085??
This has been fixed by replacing R6905
I'm working on figuring out why I am getting voltage on pin 1 of U7000. I traced back to R7085 (470k resistor) and on a known working I get 16.87v left side and 6.89v right side the one I am currently trying to fix is 16.66v left side and 15.91v right side. I tested the resistance while still mounted to the board and I am getting 470k which is correct. Is my multimeter wrong? or is there another reason that the voltage is making it through to the other side of R7085??
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going going gone
Thanks Dadioh,
I think i will need another palmrest but i can't be sure if this going to sort things out. Anyway the laptop is on ebay uk now.
Regards
Thanks Dadioh,
I think i will need another palmrest but i can't be sure if this going to sort things out. Anyway the laptop is on ebay uk now.
Regards
Ppvcore_s0_cpu
Hi Everybody, I'm back after doing my remodeling project. I have liquid spill MBP Early 2011 13' that I was able to partially repair.
Original Symptoms:
-no power
-no charging
I was able to fix these two and now the laptop powers and charges but won't boot. The issue is similar to my other repairs and the problem is with CPUIMVP_PGOOD which supposed to be 3.3V but instead I have 0V. Tracing it back this signal is produced from U7400. This chip is controlled by other inputs and is directly related to N-Channel FET (Q7510) I believe these two chips are handshaking and when looking at the schematic are feeding signals from each other. I'm trying to figure out what is the sequence so I can trace it back to the component that is causing U7400 not to product CPUIMVP_PGOOD.
Hi Everybody, I'm back after doing my remodeling project. I have liquid spill MBP Early 2011 13' that I was able to partially repair.
Original Symptoms:
-no power
-no charging
I was able to fix these two and now the laptop powers and charges but won't boot. The issue is similar to my other repairs and the problem is with CPUIMVP_PGOOD which supposed to be 3.3V but instead I have 0V. Tracing it back this signal is produced from U7400. This chip is controlled by other inputs and is directly related to N-Channel FET (Q7510) I believe these two chips are handshaking and when looking at the schematic are feeding signals from each other. I'm trying to figure out what is the sequence so I can trace it back to the component that is causing U7400 not to product CPUIMVP_PGOOD.
