SMC Issue on MBP 13 - Hardware Troubleshooting Guide

[G35C]

Help with 2008 Aluminum Macbook

Hi Guys,

So I'm helping out a fellow with a 2008 Aluminum MacBook. The battery stopped showing up in the tool bar so the user bought a new battery. The new battery shows up and charges however when you disconnect the ac power it shuts off as if there is no battery. A SMC reset and Pram reset were done to no avail. Sometimes when the AC power is left in the green led will switch to orange then green back to orange flip flopping until a clean SMC reset is done. With SMC reset it will stay orange and charge battery. So far I have tested with a known good battery, DC Jack, Battery Indicator board with cable, and Battery cable and board all with no changes in results. Is there anything else that can be pointed out for me to test?

 

[Dadioh]

Hi Guys,

So I'm helping out a fellow with a 2008 Aluminum MacBook. The battery stopped showing up in the tool bar so the user bought a new battery. The new battery shows up and charges however when you disconnect the ac power it shuts off as if there is no battery. A SMC reset and Pram reset were done to no avail. Sometimes when the AC power is left in the green led will switch to orange then green back to orange flip flopping until a clean SMC reset is done. With SMC reset it will stay orange and charge battery. So far I have tested with a known good battery, DC Jack, Battery Indicator board with cable, and Battery cable and board all with no changes in results. Is there anything else that can be pointed out for me to test?

Check to see if you have G3HOT with just the battery attached. There is a diode OR that feeds the G3HOT signal from the DCin as well as the battery. If that diode OR is bad then you would only be able to boot and run with dc plugged in.

 

[G35C]

Check to see if you have G3HOT with just the battery attached. There is a diode OR that feeds the G3HOT signal from the DCin as well as the battery. If that diode OR is bad then you would only be able to boot and run with dc plugged in.

Ok so this 2008 Model is slightly different so i'm not sure where the G3HOT is for testing. Can you literally point me in the right direction. THanks so much!!

 

[Astroboy907]

Hey all, if you have been helped by this thread and by users such as Dadioh's awesome help, I urge you to chime in on your opinion of starting a dedicated Mac Repair sub-forum here. If you are against the idea, or don't feel the need for a dedicated forum to repair macs, your opinion is helpful too. I am just trying to see if a lot of users think it is a decent idea or not. Please also note that I am not affiliated with Macrumors or their moderation team in any way. This is simply a users idea, and may not come to reality. Either way, your opinion would be appreciated.

Thanks!
Thomas

 

[Dadioh]

Ok so this 2008 Model is slightly different so i'm not sure where the G3HOT is for testing. Can you literally point me in the right direction. THanks so much!!

One of the 2 pads below carries the G3Hot 3.4V (note it is not actually G3Hot but it will tell you if you have 3.4V on the board). So with magsafe connected check it and see if you have 3.4V on one of these pins. Then unplug the magsafe (with battery installed) and see if you still have 3.4V there.

 

[G35C]

One of the 2 pads below carries the G3Hot 3.4V (note it is not actually G3Hot but it will tell you if you have 3.4V on the board). So with magsafe connected check it and see if you have 3.4V on one of these pins. Then unplug the magsafe (with battery installed) and see if you still have 3.4V there.

Perfect. Thank you for that. So i get 3.4V with magsafe and 1.4 with battery. You mentioned a diode OR from the battery; where is that?

 

[Dadioh]

Perfect. Thank you for that. So i get 3.4V with magsafe and 1.4 with battery. You mentioned a diode OR from the battery; where is that?

That explains it. I suspect that diode is bad. I have provided the info below but you should have access to the schematic and boardview file in order to be able to do this yourself at some point. You look at the schematic and see that D6905 is the diode OR that I mentioned. You search for D6905 in the boardview file and see that it is on the back of the board in the location shown. For reference next time you are looking for a component

 

[Sheridansystems]

G3hot mbp 13" 2011 location help?

Hello,
Can someone tell or show me the location of the g3hot on the MacBook Pro 13" 2011?
I am trying to diagnose a no post issue, after a spill. I have cleaned it using the recommended 98% iso, and toothbrush, even one step further, using a Ayoue 9070 PCB cleaner. (Sorry 91% iso)
Thanks in advance

 

[Astroboy907]

I have cleaned it using the recommended 98% iso, and toothbrush, even one step further, using a Ayoue 9070 PCB cleaner.

Where can you find 98% iso? Here I can only find 91%, good but not perfect. Did you special order it?

 

[rufunky]

MBP Mid 2010

Can someone tell me what the voltage should be coming through R7020? Also what number pin does it come in on U7000?

 

[mac-n-sauce]

Can someone tell me what the voltage should be coming through R7020? Also what number pin does it come in on U7000?

16.5-18.5v
Pin 27

 

[rufunky]

16.5-18.5v
Pin 27

Thanks, I'm pretty sure I was getting nothing on either side of that resistor today when I checked earlier. I'm gonna backtrack, I'll follow up tomorrow when I get back to the shop.

 

[rufunky]

MBP mid 2010

So, I backtracked to Q7085 and I am getting 16.5v on pins 1-2-3 / 15.5v on 4 / 0.566v out of pin 5. I should be getting 6.9v on pin 4 and 16.5v on pin 5 ( tested a known good MBP ).Does this indicate I need to replace Q7085 ?

EDIT:

Also I am getting 16.5v -17v on Pins 1-2-3-4-5 of Q7080. Is this correct? Shouldn't pin 4 be different?

 

[Sheridansystems]

G3HOT location for your 2011 MBP 13"

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.

Can you tell me where the G3HOT is on the MBP 2011 13"? I can't seem to find a reference to it on this thread, but you sound like you would know.
Thanks

Found it!!! Thanks, I love this forum, and I don't just throw around that word. Seriously thanks

 

[G35C]

That explains it. I suspect that diode is bad. I have provided the info below but you should have access to the schematic and boardview file in order to be able to do this yourself at some point. You look at the schematic and see that D6905 is the diode OR that I mentioned. You search for D6905 in the boardview file and see that it is on the back of the board in the location shown. For reference next time you are looking for a component

Thanks for the detailed PICs!! Your patience and contribution is much appreciated!!!

 

[Dadioh]

So, I backtracked to Q7085 and I am getting 16.5v on pins 1-2-3 / 15.5v on 4 / 0.566v out of pin 5. I should be getting 6.9v on pin 4 and 16.5v on pin 5 ( tested a known good MBP ).Does this indicate I need to replace Q7085 ?

EDIT:

Also I am getting 16.5v -17v on Pins 1-2-3-4-5 of Q7080. Is this correct? Shouldn't pin 4 be different?

Pin 4 is the gate of the FET. Think of it as the signal to turn the FET on.

16.5V comes from charger to the drain of Q7080. To turn the FET on you need pin 4 to be pulled low compared to the 16.5V. That is done by the charger chip U7000 pin 26 SGATE being pulled low. If it is not being pulled low then then the charger is not happy.

Once SGATE is pulled low then you have 16.5V showing up at Q7085. In order for it to be turned on you need U7000 to pull pin 4 of Q7085 low with AGATE pin 1 of U7000.

So it is a series of 2 FET's, both of which need to be turned on for 16.5V to be presented to the charger FET Q7030. If Q7030 does not have 16.5V to work with then it can not generate 12.5V for the charging circuit.

Hope that helps.

 

[laptech]

cpu fans stop and starting

Hi,

I need abit of advice on where i should be focusing my efforts on with a particular fault. I'm still learning my way through mac logic boards, so far learned two specific faults, no g3hot and no green led on the magsafe. The fault in question is when the cpu fan starts then stops and repeats this cycle until you pull the power supply out. The logic board does not post, just has the cpu fan starting and stopping then repeats the process again, starts then stops after a few seconds. Could it be a power fault so when the voltage hits the faulty part the board sort of resets itself, hence the start then stop of the fan because the power is going on and off?. Could it be a logic fault with the SMC?. I've never come across this fault before and i am abit lost as to where i should start looking. The board in question is a k90i, 820-2936-B. I've been looking through the schematic and just lost where to start with this particular fault.

Any help would be greatly appreciated.

kind regards
Rog

 

[rufunky]

Hi,

I need abit of advice on where i should be focusing my efforts on with a particular fault. I'm still learning my way through mac logic boards, so far learned two specific faults, no g3hot and no green led on the magsafe. The fault in question is when the cpu fan starts then stops and repeats this cycle until you pull the power supply out. The logic board does not post, just has the cpu fan starting and stopping then repeats the process again, starts then stops after a few seconds. Could it be a power fault so when the voltage hits the faulty part the board sort of resets itself, hence the start then stop of the fan because the power is going on and off?. Could it be a logic fault with the SMC?. I've never come across this fault before and i am abit lost as to where i should start looking. The board in question is a k90i, 820-2936-B. I've been looking through the schematic and just lost where to start with this particular fault.

Any help would be greatly appreciated.

kind regards
Rog

I had this exact same issue on one of my MBP. Come to find out I had missed some corrosion that had set in from the liquid spill and it was arching to another component. Check areas specifically around the edge of the logic board with a 30x loop or microscope. Just my two cents

 

[widerstand]

MacBook Pro 5,5 mid 2009 charging problems

Hello to all!
After some exprerience with a bad charger my DC board went bad.
I replaced it, but since then charging is like hell.
I plug in the MagSafe, it detects, so goes to green, but after some charging the computer "drops" it. reconnecting it does not help, only plugging out it from the mains, reversing polarity (yes, the AC polarity in the wall outlet).
sometimes when i connect it the computer shuts off.
I removed all the components, put the logic board on the desk, only DC board connected, no battery. the symptom is now blinking green light, battery indicator light(8-LED on the side) is also dropping, so i don't get the knight-rider style light effect continously.
once the dc board sparkled on the connection, making the computer shut down.
is it some major colding capacitor (or what are they called in english? ceramic caps connected to mains voltage and ground) problem on the logic board?
Tried since then well-known chargers and DC boards as well, so yes, logic board problem...
i have seen some advance in board view files and programmes, i would be happy to host a mini ftp for these files in one directory, making them more widespread and easier to find... maybe a blog would do for step by step repairs, so there won't be any re-apperaing problems on the thread.
maybe mine is also answered once, but couldn't find the solution for it.

and on an other problem, maybe help some:
one of my colleagues inserted after screen replacement the WiFi card cable in the Wifi/BT card reversed.
ended up in a fried logic board never detecting wifi again, and a computer, that was impossible to shut down, it just restarts every time. this symptom is always a sign of a bad side re-inserted wifi cable.
so the wifi can be repaired by replacing the coil near the connector?
Strangely, the BlueTooth works flawlessly.

Greeitngs

widerstand

----------

Hi,

I need abit of advice on where i should be focusing my efforts on with a particular fault. I'm still learning my way through mac logic boards, so far learned two specific faults, no g3hot and no green led on the magsafe. The fault in question is when the cpu fan starts then stops and repeats this cycle until you pull the power supply out. The logic board does not post, just has the cpu fan starting and stopping then repeats the process again, starts then stops after a few seconds. Could it be a power fault so when the voltage hits the faulty part the board sort of resets itself, hence the start then stop of the fan because the power is going on and off?. Could it be a logic fault with the SMC?. I've never come across this fault before and i am abit lost as to where i should start looking. The board in question is a k90i, 820-2936-B. I've been looking through the schematic and just lost where to start with this particular fault.

Any help would be greatly appreciated.

kind regards
Rog

My A1342 MB White UniBody does the same thing,but it lacks the 1.05V CPU voltage...

 

[rufunky]

Pin 4 is the gate of the FET. Think of it as the signal to turn the FET on.

16.5V comes from charger to the drain of Q7080. To turn the FET on you need pin 4 to be pulled low compared to the 16.5V. That is done by the charger chip U7000 pin 26 SGATE being pulled low. If it is not being pulled low then then the charger is not happy.

Once SGATE is pulled low then you have 16.5V showing up at Q7085. In order for it to be turned on you need U7000 to pull pin 4 of Q7085 low with AGATE pin 1 of U7000.

So it is a series of 2 FET's, both of which need to be turned on for 16.5V to be presented to the charger FET Q7030. If Q7030 does not have 16.5V to work with then it can not generate 12.5V for the charging circuit.

Hope that helps.

Thank you Dadioh, that helps a lot. How tolerant are the U7000 chips? is it possible I heated it up one to many times when I replaced it?

 

[Dadioh]

Thank you Dadioh, that helps a lot. How tolerant are the U7000 chips? is it possible I heated it up one to many times when I replaced it?

They are fairly tolerant to the solder heating process. In my experience replacing these, the most common issue after replacement is that I have not achieved a solder joint on one or more of the pins. I detect this either visually by holding my board at an angle under my microscope and inspecting the joints or by measuring the resistance between each pin and ground. If one of the resistance measurements seems to be out by a lot then it "may" indicate that pin is not soldered correctly.

My soldering technique on these QFNs is to clean off all the solder from the pads and then apply a small dot to the center thermal pad. Apply flux and then carefully position the QFN on the pads. Examine the 4 sides from an angle to make sure the pads are lined up. Then, with air flow on a low setting (so that it does not dislodge the package) I apply heat until it I see the solder has melted. I then tap it down with my tweezers to make sure the thermal pad is soldered. Remove heat and let cool for about 20 seconds and then examine the 4 sides to make sure the QFN pads are still lined up. Then use a soldering iron to go around the perimeter, soldering each lead. The trick is getting enough heat to each pin to get the solder to flow. Often I drag a bead of solder across the row of pins and let the solder ball wick onto the pins. If you bridge any pins then just apply some more flux and draw it away with the tip of the iron to separate the bridge. It is painstaking work and sometimes pads do not get soldered properly so it takes a second pass.

I would concentrate first on whether the QFN leads are all soldered correctly before assuming that the device is bad. Good luck.

 

[kizzy]

mbp 13" 2011

Hi, sorry for butting in – my first post.

I have a MBP 13” 2011 i5. It was totally dead with some liquid damage. After thorough cleaning and replacement of Mag board it's becoming to look salvageable!
The situation now is :
1) connect the mag and it starts immediately (without pressing the power button).
- disconnect keyboard cable – still the same
2) with battery only won't start with or without the power button. But will start off the pads with battery only?

3) with battery connected, connecting the mag starts it straight away (without power button).
Disconnecting the mag it continues to operate with the battery and can only be turned off by removing the battery?

I'm having a difficult time finding and following schematics so any help would be greatly appreciated.

I've worked on non-mac laptops for many years and only recently tried looking at macs. I must say I've never come across a laptop site, in all my years (quite a lot) that could compare with this one. I'm currently on page 50 or thereabouts and i'm fascinated.

Are there any tutorials on following schematics and or using boardview files?

again, sorry for butting in.

Regards

tim

 

[rufunky]

They are fairly tolerant to the solder heating process. In my experience replacing these, the most common issue after replacement is that I have not achieved a solder joint on one or more of the pins. I detect this either visually by holding my board at an angle under my microscope and inspecting the joints or by measuring the resistance between each pin and ground. If one of the resistance measurements seems to be out by a lot then it "may" indicate that pin is not soldered correctly.

My soldering technique on these QFNs is to clean off all the solder from the pads and then apply a small dot to the center thermal pad. Apply flux and then carefully position the QFN on the pads. Examine the 4 sides from an angle to make sure the pads are lined up. Then, with air flow on a low setting (so that it does not dislodge the package) I apply heat until it I see the solder has melted. I then tap it down with my tweezers to make sure the thermal pad is soldered. Remove heat and let cool for about 20 seconds and then examine the 4 sides to make sure the QFN pads are still lined up. Then use a soldering iron to go around the perimeter, soldering each lead. The trick is getting enough heat to each pin to get the solder to flow. Often I drag a bead of solder across the row of pins and let the solder ball wick onto the pins. If you bridge any pins then just apply some more flux and draw it away with the tip of the iron to separate the bridge. It is painstaking work and sometimes pads do not get soldered properly so it takes a second pass.

I would concentrate first on whether the QFN leads are all soldered correctly before assuming that the device is bad. Good luck.

How would I know what the resistance of each pin should be and would I measure this off a ground anywhere on the logic board or a specific pin on the U7000?

I have been using my stereo microscope and angling the board to check the joints and they seem ok but it is difficult to get a good angle so I just ordered a 30x loop. Hopefully that will help.

 

[Joris01]

Hello everyone,

I am a new member on this forum.

Introduction:
- 24 years old
- Netherlands,
- Employed (engineer but not a technician...).

The reason why I registered is that my MBP mid 2010 (unibody) only starts with the SMC bypass and while reading this topic I found out there is a lot of knowledge in here! The problem I'm having is probably described by someone else already in this topic, sorry if this is considered as a double post...

In short:
- Charger = ok
- Magsafe indicator = not glowing, not even a dim light as some say
- Battery = depleted, with replacement battery the MBP works perfect (but battery is not charging)
- System will not turn on with magsafe alone (battery taken out).
- Boots only with SMC bypass, battery is not charging and not being recognized (I think it's because it's depleted) .
- Apple Hardware Test = ok, no errors found.
- No liquid or fall damage


I'm suspecting the DC-in (magsafe board) is faulty, is this a possibilty based on my symptoms or should I look elsewhere? Is there an easy way to test this or should I just order a new one and see? I do not have Voltage-meter tools....

Many thanks!

Joris

 

[cmdrdata]

Hello everyone,

I am a new member on this forum.

Introduction:
- 24 years old
- Netherlands,
- Employed (engineer but not a technician...).

The reason why I registered is that my MBP mid 2010 (unibody) only starts with the SMC bypass and while reading this topic I found out there is a lot of knowledge in here! The problem I'm having is probably described by someone else already in this topic, sorry if this is considered as a double post...

In short:
- Charger = ok
- Magsafe indicator = not glowing, not even a dim light as some say
- Battery = depleted, with replacement battery the MBP works perfect (but battery is not charging)
- System will not turn on with magsafe alone (battery taken out).
- Boots only with SMC bypass, battery is not charging and not being recognized (I think it's because it's depleted) .
- Apple Hardware Test = ok, no errors found.
- No liquid or fall damage


I'm suspecting the DC-in (magsafe board) is faulty, is this a possibilty based on my symptoms or should I look elsewhere? Is there an easy way to test this or should I just order a new one and see? I do not have Voltage-meter tools....

Many thanks!

Joris

Before doing anything drastic, disconnect battery and magsafe. Clean magsafe PLUG and CONNECTOR with isopropyl alcohol. Ensure that contact pins on the plug is not stuck. It should be somewhat springy. If it is a bad DCIN board, be careful when testing replacing it as many people in this forum accidentally short it to the logic board causing more serious damage while testing out of the chassis.