SMC Issue on MBP 13 - Hardware Troubleshooting Guide

[nicoar10]

Hi there! Thanks for your reply, I am able to use the MBP from battery and boot to desktop with an external display.

I have attached the image with the burnt fuse. As of now, It wont charge or power on via magsafe.

I have a multi-meter on hand, It will be good if you can advise on the various contact point for the readings. and the correct value i should get. Thanks again!

Please take a pic from other side board

 

[varungargi]

Any one with Schematics and brd file for MacBook Air A1466 J43 MLB 820-3437 051-9800

I am looking Looking for schematics for Macbook Air 2013 13"
Its J43 Board numbers :- 051-9800 and 820-3437

Thanks in advance.

I can see it on a Poland website but i cant download :-
http://www.elvikom.pl/schematic-apple-macbook-air-a1466-j43-mlb-820-3437-051-9800-t31740.html

 

[varungargi]

you guys have the board view MacBook Air A1370 820-2796-a ?
I have the schematics... needing the boardview...
thanks

Brd file for K99 A1370

 

[ZZZAC]

I am looking Looking for schematics for Macbook Air 2013 13"
Its J43 Board numbers :- 051-9800 and 820-3437

Thanks in advance.

I can see it on a Poland website but i cant download :-
http://www.elvikom.pl/schematic-apple-macbook-air-a1466-j43-mlb-820-3437-051-9800-t31740.html

here

 

[varungargi]

here

Thanks ZZZAC !

 

[ZZZAC]

Thanks ZZZAC !

if it helps i found my own board had missing g3hot caused by an open circuit resistor. It also had a blown backlight fuse caused by a damaged display assembly and a blown WLED chip. good luck

 

[nicoar10]

820-3115b power from battery - not magsafe

Hi boys, here arrived this board.
First was water spilled detected, everything cleaned now.

For one day works perfectly, now just power on from battery only.
When magsafe connected dim light on magsafe.

Checked lines:

G3hot OK 3,47v

I check U6900 and U6901 and see when magsafe is connected SMC_BC_ACOK_VCC is shorted to ground. 0,0V
and L6995 inductor make a little sound like a clock.
i think this line is connected with SMC ?

Is this sound a overvoltage?

Regards

 

[ZZZAC]

Hi boys, here arrived this board.
First was water spilled detected, everything cleaned now.

For one day works perfectly, now just power on from battery only.
When magsafe connected dim light on magsafe.

Checked lines:

G3hot OK 3,47v

I check U6900 and U6901 and see when magsafe is connected SMC_BC_ACOK_VCC is shorted to ground. 0,0V
and L6995 inductor make a little sound like a clock.
i think this line is connected with SMC ?

Is this sound a overvoltage?

Regards

If your SMC BC ACOK is shorted to ground then its suggested you replace u6900 and possible u6901 (i saw them go in pairs, if one fails the other can aswell) But to be sure first pull the component of the board, and check the resistance to ground.

also check resistor R7005

 

[nicoar10]

If your SMC BC ACOK is shorted to ground then its suggested you replace u6900 and possible u6901 (i saw them go in pairs, if one fails the other can aswell) But to be sure first pull the component of the board, and check the resistance to ground.

also check resistor R7005

Thanks!
i checked before

desolder U6901 and magsafe connected pin4 is not shorted to ground. Anyway i replaced U6901 and U6900. R7005 is ok and working with 16,5v.

Is strange, even this inductor sound like a overvoltage. Im begin to think is a SMC issue.

 

[tiagobaracho]

Brd file for K99 A1370

thanks so much.. i seached A LOT and did not find.... May you tell me how did you find it ?
I already tried to find a buck file with a lot of schematics together , but never find.... I am always fixing macbooks and everytime i need to search a schematics is a pain .... Do you have a large collection of schematics? I guess i have 6 - 7 only..

 

[ZZZAC]

Thanks!
i checked before

desolder U6901 and magsafe connected pin4 is not shorted to ground. Anyway i replaced U6901 and U6900. R7005 is ok and working with 16,5v.

Is strange, even this inductor sound like a overvoltage. Im begin to think is a SMC issue.

Is this working now then?

I have a 820-3115 ive had for ages, got everything working but power light so i jumped to conclusion an tried replacing the smc, however i dont realy have the skill for the newer SMC chips or things like the graphics GMUX chips, i always seem to pull pads on the chip when re balling so im ordering from china.

Anyhow yesterday i was using it to compare resistors on another 3115 board and funnily enough r7005 is way out of spec (think its like 3.2k rather than 20ohm)
so im fairly sure this is probably why the charger wasnt sensed and i probably pulled the smc as a misdiagnosis

Oh well, ill get it going one day lol

 

[nicoar10]

Is this working now then?

I have a 820-3115 ive had for ages, got everything working but power light so i jumped to conclusion an tried replacing the smc, however i dont realy have the skill for the newer SMC chips or things like the graphics GMUX chips, i always seem to pull pads on the chip when re balling so im ordering from china.

Anyhow yesterday i was using it to compare resistors on another 3115 board and funnily enough r7005 is way out of spec (think its like 3.2k rather than 20ohm)
so im fairly sure this is probably why the charger wasnt sensed and i probably pulled the smc as a misdiagnosis

Oh well, ill get it going one day lol

Still no power from magsafe, only from battery.
I will check SMC resistors.

 

[tiagobaracho]

Still no power from magsafe, only from battery.
I will check SMC resistors.

nicoar10, i see that you have a lot of schematics... Would you have a problem to make a zip file with those and share ? I could also reply here to those in need of a schmeatics and when i receive a macbook here to fix I would have it already... I would be greatly appreciated if you can do that.
Thanks

 

[nicoar10]

nicoar10, i see that you have a lot of schematics... Would you have a problem to make a zip file with those and share ? I could also reply here to those in need of a schmeatics and when i receive a macbook here to fix I would have it already... I would be greatly appreciated if you can do that.
Thanks

I got a lot of them but i post link when people need it. Let me know what are you looking for

 

[tiagobaracho]

I got a lot of them but i post link when people need it. Let me know what are you looking for

I have 9 macbook pros here right know... I will have to open up and ask.... thats why i asked you if you could share a quite a few in a zip file.... Is it bad for you somehow to do it ?
I am also needing to fix a Mac Pro that does not do anything and when i click on the diag buttom it lights 5v stdby ... But when the power supply is connected to the mains, i can find 5.v and 3.3... I am not sure if it should have another 5v other than this of if the mainboard is thinking there is no 5v stdby...
I have first to be sure the power supply is OK or bad before reaching for the mainboard but i could not even find the pin out of the power supply DPS 980BB
When a short with ground one of the 3.3 v it dos start and i have 12v on the larger connectors.
Have you worked on those ?
Thanks

 

[tiagobaracho]

do you have the schematics for 820-2337-A ? and board view ? this is the mac pro i was talking about.. Thanks

 

[nicoar10]

do you have the schematics for 820-2337-A ? and board view ? this is the mac pro i was talking about.. Thanks

sorry, not mac pro. Only MBP and MBA. Maybe some iMac schem

 

[smithtony22]

Here is a new, unrelated issue but maybe some of the board repair experts on this thread have some ideas.

I have a 2010 MBP13 2.4GHz that I got with liquid damage. I got it working for a few weeks but it suddenly developed a problem where it would not start up but would shut down part way through the chime. Holding down the power button until it flashed would allow it to boot and things "seemed" fine. I ran Apple Hardware Test and it failed with code 4SNS/1/40000000:ICOC-65.828

The SNS means "Sensor" and I suspect ICOC is something about "Over Current". So I thought maybe one of the current sensors is broken.

I installed iStat Menus on the machine and had a look at the sensor data and it is all over the place. So it is not just one sensor that is wrong but it is across the board for voltage and current sensors. But there doesn't seem to be a common failure point that would lead to so many apparently unrelated sensor circuits to be wrong. Common denominator is the SMC but a bad SMC probably would kill the whole board.

Am I missing something obvious or does anyone have any ideas?

Hi there possible short to GND_SMC_AVSS as this is the common denominator of all sensors.

I know this was from a while back but had exactly the same problem and thought it might help someone to share a possible fix for this or at least a point in the write direction (at least for a macbook pro 13inch 2010 logic board).

Had same error code 4SNS/1/40000000:ICOC and all sensors showing wrong values (or out of tolerance, which where high in my case). Symptoms are turn on and cuts out halfway through chime. Turns on with power button held after a few attempts. Installed istat after diag produced sensor fault (sns ICOC) and showed all sensors out of wack.

Bit of luck finding that U5010 was slightly warm when off, which indicated some short on the output side or itself had shorted. Found that the two capacitors (C5025 & C5026 both on the output pin 8 of U5010) where shorted. Short from PP3V3_S5_AVREF_SMC (output on pin 8 of u5010) to GND_SMC_AVSS. This GND_SMC_AVSS is ground for all the sensors on the board. This explained funny values and not starting due to smc not being happy.

The culprit being C5025 shorted, replaced and powers on and works fine.

If it sounds like I am a noob, its because I am. Just thought this may help or be a possible solution for someone, with all sensors being wacky. Almost has to be tied to a short to GND_SMC_AVSS as this is the common denominator of all sensors.

 

[tiagobaracho]

nicoar10 or someone else that knows too,
Could you explain how the brightness works ? I lowered the bright to zero and rebooted one mac air... when it reboot it just flashes rapidly then backlight is of.... when it goes into the OSX if i rise the bright it light up normally... so i tested the U9000 FPF1009 and all voltages are the same there... 3.3 volts on input and output... even with the bright to zero...

I am asking because in another situation I could be working on a motherboard with good led driver and just some other problem ( resistor or capacitor) making the brightness adjust to zero...
So, how does it works ? If the led voltages are the same at full bright and low bright ? i did not get how its done..
Thanks

 

[ZZZAC]

nicoar10 or someone else that knows too,
Could you explain how the brightness works ? I lowered the bright to zero and rebooted one mac air... when it reboot it just flashes rapidly then backlight is of.... when it goes into the OSX if i rise the bright it light up normally... so i tested the U9000 FPF1009 and all voltages are the same there... 3.3 volts on input and output... even with the bright to zero...

I am asking because in another situation I could be working on a motherboard with good led driver and just some other problem ( resistor or capacitor) making the brightness adjust to zero...
So, how does it works ? If the led voltages are the same at full bright and low bright ? i did not get how its done..
Thanks

your getting a little confused. U9000 and 3.3v is just logic circuitary to turn the panels display on.
your backlight voltage comes from the WLED driver often labled U9701 or U9700 *not sure about some airs though)

the IC controlls the power going to the backlight via a feedback resistor i believe, the backlight is enabled by the wled enable resistor, or the fets that come just after the fuse (gate signal usually from the chipset)

I have no clue what could cause the flashing backlight, however i recently had an air that had a shored display panel, on a known good display even after replacing the fuse i had no backlight, i found the WLED driver to be damaged but not damaged enough to cause the fuse to blow. replacing this tiny bga resolved the backlight problem.

But in reality it could be anything, best get your multimeter, in my experience its more likely a resistor has gone open circuit than a capacitor being shorted

 

[tiagobaracho]

your getting a little confused. U9000 and 3.3v is just logic circuitary to turn the panels display on.
your backlight voltage comes from the WLED driver often labled U9701 or U9700 *not sure about some airs though)

the IC controlls the power going to the backlight via a feedback resistor i believe, the backlight is enabled by the wled enable resistor, or the fets that come just after the fuse (gate signal usually from the chipset)

I have no clue what could cause the flashing backlight, however i recently had an air that had a shored display panel, on a known good display even after replacing the fuse i had no backlight, i found the WLED driver to be damaged but not damaged enough to cause the fuse to blow. replacing this tiny bga resolved the backlight problem.

But in reality it could be anything, best get your multimeter, in my experience its more likely a resistor has gone open circuit than a capacitor being shorted

ho man ! yes, you right.. i was confused... Because on the MBP the WLED driver is almost the same physical location...
Its working perfectly .. i was just wodering
I have a MBP here that has no backlight.. I bought the wled bga and i expect to fix... everything seems to be working with no backlight... I got to say... fixing other notebooks are much easier that MBP... Those black board with 1/20w resistors are sometimes hard to trobleshoot..
I recently fixed 1 sony ultrabook that had a shorted cap, one macbook with shorted cap that opened one resistor.... I am seeing a lot of those shorted caps.. when I see on microscope its cracked, and I begin to smile
I have been using my rigol dp832 power supply to help me along with my Flir E4 thermal cam... When i have a power line that its not working i add in parallel the power supply and watch on the thermal cam while increasing the volts ( until the line actual voltage) and sometimes something gets hot.... I used this way to discover both shorted caps... I find it to be very useful after some searching and not finding the problem.
In this MBP that i will change the wled, it was not powering up.. but the BROADCOM lan chip was getting 140 degrees... So i removed and now it power up but no backlight, so i bought the broadcom and the wled.. i hope it will work... I got to say.. I love fixing.. I learn so much on each MB that i work on...
I would love to know a very good curse to learn as advanced as it can be...

Thanks man

 

[ZZZAC]

Ive got a couple nightmare 820-2530 boards that have ASD failures on sensors.
If anyone has some in site to them it would be great
1.
Board only powers on if power is held for 5 seconds
i get Vp0r Above alarm limit
Ip0r (cant remember if it was low or high)
TB3T

Also the battery seems to charge intermittently
BIL lights dont work either but theres activity when the battery is hot plugged.


2.
Has been a nightmare to get this far
has had replacement SMC
Replacement charging ic
Replacement G3hot circuit (regulator, failed caps.ect)
replacement screen connector
several replacement resistors in the screen circuit
somehow still had no internal display, was missing a gate to enable the LVDS (gate was from the MCP U1400 chipset)
Reflown the chipset rather badly and now i get internal display, Seems to boot every time in smc bypas, however intermittently normally.

I get the following error's in ASD

Vn0c (MCP core current running below alarm limit)
Vp0r running above alarm limit
SMC PID sensor tripped


Proper head scratchers, And ive fought hard with these boards to get them to this point, i really dont want to give up on them now!!!

Anyone who can help is an absolute saint! i will be in debt to you forever!

----------

Oh board 2's reflow hasnt been fully successful, it fails the video controller test. considering the chipsets fairly important would it be viable to jump to conclusion that if i get it sorted properly the other issues will also be resolved?

 

[tiagobaracho]

Ive got a couple nightmare 820-2530 boards that have ASD failures on sensors.
If anyone has some in site to them it would be great
1.
Board only powers on if power is held for 5 seconds
i get Vp0r Above alarm limit
Ip0r (cant remember if it was low or high)
TB3T

Also the battery seems to charge intermittently
BIL lights dont work either but theres activity when the battery is hot plugged.


2.
Has been a nightmare to get this far
has had replacement SMC
Replacement charging ic
Replacement G3hot circuit (regulator, failed caps.ect)
replacement screen connector
several replacement resistors in the screen circuit
somehow still had no internal display, was missing a gate to enable the LVDS (gate was from the MCP U1400 chipset)
Reflown the chipset rather badly and now i get internal display, Seems to boot every time in smc bypas, however intermittently normally.

I get the following error's in ASD

Vn0c (MCP core voltage running below alarm limit)
Vp0r running above alarm limit
SMC PID sensor tripped


Proper head scratchers, And ive fought hard with these boards to get them to this point, i really dont want to give up on them now!!!

Anyone who can help is an absolute saint! i will be in debt to you forever!

----------

Oh board 2's reflow hasnt been fully successful, it fails the video controller test. considering the chipsets fairly important would it be viable to jump to conclusion that if i get it sorted properly the other issues will also be resolved?

hi ! I have replaced GPUs on notebooks and before replacement, a few were simply wierd... freezing and stuff.. I guess it can be all possible...
Have you check all voltages on osciloscope to see the level of noise in each ? sometimes a bad inductor or capacitor may leave a bad Voltage rail that would interfere all the connected CIs creating a unstable system ( fixed one notebook once that had bad cap(not shorted) close to the inductor that was creating ripples on that 3.3v line.)

 

[varungargi]

if it helps i found my own board had missing g3hot caused by an open circuit resistor. It also had a blown backlight fuse caused by a damaged display assembly and a blown WLED chip. good luck

Ahh thanks for the update . . .

I was not able to get 3.4V from G3HOT, replaced the G3HOT IC and now i get 3.4V and it boots fine.

But the Backlight seems to be a problem, for me too the fuse was blown, i replaced the fuse still no backlight. The backlight voltage is 8.25V on PPVIN_S0SW_LCDBKLT_FET and on 8.35V PPHV_S0SW_LCDBKLT.

It seems the U7710(LP8550) is a problem, is this the same WLED chip you are talking about ?

 

[ZZZAC]

hi ! I have replaced GPUs on notebooks and before replacement, a few were simply wierd... freezing and stuff.. I guess it can be all possible...
Have you check all voltages on osciloscope to see the level of noise in each ? sometimes a bad inductor or capacitor may leave a bad Voltage rail that would interfere all the connected CIs creating a unstable system ( fixed one notebook once that had bad cap(not shorted) close to the inductor that was creating ripples on that 3.3v line.)

I dont have an oscilloscope. im fairly new to the repair game, only just got myself a farnel bench power supply.

the fact i get the mcp core current error could suggest ripple on the line but i really have no way i can test for it i dont think.
strange thing is the array of issues ive found related to the mcp such as no back light or in this case no internal display, i suppose because it does allsorts if a joint is bad it can mess about with allsorts.

----------

Ahh thanks for the update . . .

I was not able to get 3.4V from G3HOT, replaced the G3HOT IC and now i get 3.4V and it boots fine.

But the Backlight seems to be a problem, for me too the fuse was blown, i replaced the fuse still no backlight. The backlight voltage is 8.25V on PPVIN_S0SW_LCDBKLT_FET and on 8.35V PPHV_S0SW_LCDBKLT.

It seems the U7710(LP8550) is a problem, is this the same WLED chip you are talking about ?

yes thats the same as the one i replaced.
Check the voltage divider resistors on the enable line for that chip. i found my resistors read far lower than there actual value, this pointed me towards the damaged wled chip, and after pulling the old chip of the value of these two resistors jumped back into spec