SMC Issue on MBP 13 - Hardware Troubleshooting Guide

tiagobaracho said:

If you do not measure short... ( 0 ohms or close),,, meaning that a capacitor that has close to 0 ohms is a bad cap... in short.. like a bridge or 0 ohms resistor.

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Okay, now I understand

There is 0 ohms across the capacitor.

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macattack600 said:

This happens still if you have changed the charging ic?

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No, I haven't changed it yet. Just got it. Now I have to find someone who has hot air soldering station. I have only soldering Iron. It has a very fine tip, but it isn't a right tool for this kind of job.

Is working with problem

dellxps15 said:

i would change u7200., but before that u can remove u7200 and check if capacitors arond are shorted.

edit: just playing with another macbook 13 2008 board 820-2327. i have r6905 =PP18V5_DCIN_CONN blown. replaced and blow again. removed u6990 and no more blown, but strange thing is that there is no short on r6905 pins..... bad u6990 ?

Click to expand...

820-2936-a

So I replaced tps51125 U7200 and check capacitor and resistor in area all are ok, now it finally starts up everything works! But There is no chime sound when it boots? I get volume about half way in itunes. No bass kind of weak sound. I check this in another machine it's not the speakers or volume setting . Does same thing. I notice bga epoxy above u7200 U6610 U6620 this is a Amplifier on schematic I need to check all this maybe I got too hot soldering? Some proggress better than none.

macattack600 said:

820-2936-a

So I replaced tps51125 U7200 and check capacitor and resistor in area all are ok, now it finally starts up everything works! But There is no chime sound when it boots? I get volume about half way in itunes. No bass kind of weak sound. I check this in another machine it's not the speakers or volume setting . Does same thing. I notice bga epoxy above u7200 U6610 U6620 this is a Amplifier on schematic I need to check all this maybe I got too hot soldering? Some proggress better than none.

Click to expand...

Hi have you done a pram reset yet. If not try it.
Regards south657

Same problem?

I have the same symptoms described in this thread, but on a relatively new 13 " rMBP (bought just under a year ago). I'm just posting this to add another data point for people searching for info on the problem.

Background. I bought a new 13" rMBP the end of last year with 16GB RAM and 1TB SSD. This is my portable for when I need something light to take places and I've only used it maybe 10 days since I bought it. It's kept in a case and has never had any spills or other damage.

Yesterday I got it out to update software. Powered it up and noticed the battery was showing 80% after about a month of being powered off which I thought quite good. I attached power to bring the battery to full charge and because I don't like doing OS updates without power attached. I first updated everything under Mavericks and a few applications including Microsoft Office. During this process I did two reboots with no problems and the battery was now reading 100% charged with the power connecter LED at solid green.

I then updated the OS to Yosemite. Everything went smoothly as far as I can tell and I then updated software that required Yosemite; Pages, Keynote etc. Then I started Parallels Desktop with the intention of updating the Windows 7 Pro install that I run virtually. Parallels pointed out that I should update to version 10 of Parallels Desktop for full compatibility with Yosemite. I duly downloaded, installed and registered this. No problems reported. Up to this point the machine had been running fine for a couple of hours.

As part of Parallels desktop, when a new version is installed it installs it's own driver software into the Windows VM. When I started Windows under Parallels it found the new drivers and started installing them. Halfway through this the machine crashed out and rebooted; screen went black followed by a restart chime. Note, not just a crash of the VM, the whole system rebooted spontaneously. I logged back in, restarted Parallels, went in to Windows and it resumed the driver install. This time the screen started corrupting and then another spontaneous reboot occurred.

This time however, when the grey apple appeared on the boot screen the background was covered in green snow. This lasted a few seconds and then the screen went black and is now in the state described in this thread. The power button is unresponsive and to all intents I have a dead machine. I've tried the SMC reset and holding down power and alt to no effect.

Fortunately I don't have any local data on the machine as everything important is accessed over the network. All I have lost is the time taken to install software. Also the machine is covered by Applecare for another 2 years+ so I can kick this back to Apple and let them sort it out. I'm just posting this in case other people have similar experiences. In particular I'm a bit suspicious about the two crashes whilst installing drivers inside the Parallels VM. Of course it could be completely coincidental, but I don't like coincidences. My understanding of that is that the VM should be completely sandboxed from the rest of the machine and should not be able to cause reboots like that.

South657 said:

Hi have you done a pram reset yet. If not try it.
Regards south657

Click to expand...

No this has to do with the resistors coming from the 5 volt there are 3 amplifier ic's they are under the bga epoxy balls left and right mine is north of the power ic I found it last night it may have blown the amplifier ic's I need to figure out a way remove the epoxy from it and test for short or just replace them. Originally I shorted the the power ic in testing with the wrong probes so it could have stemmed up from it.

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macattack600 said:

820-2936-a

So I replaced tps51125 U7200 and check capacitor and resistor in area all are ok, now it finally starts up everything works! But There is no chime sound when it boots? I get volume about half way in itunes. No bass kind of weak sound. I check this in another machine it's not the speakers or volume setting . Does same thing. I notice bga epoxy above u7200 U6610 U6620 this is a Amplifier on schematic I need to check all this maybe I got too hot soldering? Some proggress better than none.

Click to expand...

glad u fixed it or at least it boot. if no chime, but pc start normally, do you hear sound in osx like mp3 player .... dunno wich speaker make the chime , if left or right. one speaker is down the mainboard. one is right down dvdrom. try also a pram reset, as it will reset that volume adjustment.
http://support.apple.com/kb/ht1533

wesk18 said:

Hello All,

I'm trying to fix my friends mac book, the motherboard is a 820-2879-b, it sees the battery and charger but it wont power on i tried jumping the two pins with no luck, i look for any burnt components didn't find any, where should i start checking?

Click to expand...

first check the white fuse down battery connector and see if u have 12.5 volt.

check on smc bypass pins if 3.42volt are present.

on back of board, check at coils if you have 3.3 and 5 volt present (with charger)

ps: charger light is solid green ?

rufunky said:

Do you have the link because I only saw lots of 1000? Also, here is the 820-2915 shcem you wanted.

Click to expand...

Hello,

Have you a boardview too? I need a bv for 820-2915. i have some burned component but only with schematics hard to find some parts.

Hi,

This is a Macbook Unibody 13" Late 2008 Aluminum - MB467LL/A - MacBook5,1 - A1278 - 2254 and the Logic Board is a 820-2327-a

Symptoms :

- No boot on battery
- No boot on A/C sector
- MagSafe Light dim green (never orange)
- Macbook Boot with SMC bypass (high speed fan and battery not detected X) symbol)

What I Made :

- I changed the DC/IN Board : No Change
- I Cleaned the board with alcohol : No Change
- Ordered a Battery Connector but not received yet
- Tried a good know Battery and Magsafe (directly in a Apple Store) but same issue than above

Could you please give me advice to know what I have to test/check first ? I guess that's something related to the SMC but what ...

Thank you for your help,
Regards,
Tonuz

dellxps15 said:

i would change u7200., but before that u can remove u7200 and check if capacitors arond are shorted.

edit: just playing with another macbook 13 2008 board 820-2327. i have r6905 =PP18V5_DCIN_CONN blown. replaced and blow again. removed u6990 and no more blown, but strange thing is that there is no short on r6905 pins..... bad u6990 ?

Click to expand...

i've changed u6990, and r6905 blown again... any suggestion on that ?



edit2: after change almost all capacitors near u6990, it was the same till ive removed the coil. after coil removed L6995, no more r6905 blow, but voltage at coil is 13,32 instead of 3.42.....

r6995 is 348, and r6996 is 200k.

u6990:
pin 1 is 15.5 volt
pin 2 0volt
pin3 15.5 volt
pin4 gnd
pin 5 is 13.32volt
pin 6 is 10volt
pin7 is 0volt
pin 8 is 0.6volt.

dellxps15 said:

i've changed u6990, and r6905 blown again... any suggestion on that ?



edit2: after change almost all capacitors near u6990, it was the same till ive removed the coil. after coil removed L6995, no more r6905 blow, but voltage at coil is 13,32 instead of 3.42.....

r6995 is 348, and r6996 is 200k.

u6990:
pin 1 is 15.5 volt
pin 2 0volt
pin3 15.5 volt
pin4 gnd
pin 5 is 13.32volt
pin 6 is 10volt
pin7 is 0volt
pin 8 is 0.6volt.

Click to expand...

yes you can have shorted coild that would make the IC u6990 blow the fuse... try to replace the coil... This is uncommon problem, but if you had water damage it can for sure short the coil and when it oscillate would be 0 ohms instead the coil..
this is a simple problem to solve.. .dont worry... I would connect a 3.42 v power to the 3.42 line and see if its shorted or not...... Something else to check

Hi,

i still have the problem with my Macbook A1278 mid2010 page100.

i measured the pins of U7000. Pin 1-14 ok! But Pin 15-28 is not correct! No or to low voltage on them. So no power on with Magsafe (green LED turns on, but no charging). Boot only with batterie!

Anyone an idea?

regards

////////EDIT: SOLVED! Board is now charging

tiagobaracho said:

yes you can have shorted coild that would make the IC u6990 blow the fuse... try to replace the coil... This is uncommon problem, but if you had water damage it can for sure short the coil and when it oscillate would be 0 ohms instead the coil..
this is a simple problem to solve.. .dont worry... I would connect a 3.42 v power to the 3.42 line and see if its shorted or not...... Something else to check

Click to expand...

tnx for reply, but as i said, with coil removed at coils pins i have 13.3 volt on pin 1 and 0 volt on in 2.... while i should get 3.42 volt there....

to blow was a resistor, not fuse

dellxps15 said:

tnx for reply, but as i said, with coil removed at coils pins i have 13.3 volt on pin 1 and 0 volt on in 2.... while i should get 3.42 volt there....

to blow was a resistor, not fuse

Click to expand...

its a 470 ohms fuse too....Its made to blow if some short happens..
Do you know how this coil works ? You have to have a oscilloscope to see that 13.3 volts.. Its not a RMS voltage.. its a high frequency oscillation that builds up voltage on the coil..
On leg of the coil is GND ( 0 v) an the other one is the IC output... It can output the VCC voltage .. depending on the frequency the coil will build different voltages outputs... you cannot measure without the coil, would not mean much......Or you can with a oscilloscope just to be sure the IC is working..

smithtony22 said:

Hi
did you ever manage to solve this issue? I have same board (820 3115). Been pulling my hair out trying to find what is the cause of this?

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Originally Posted by ZZZAC View Post
Hi guys i have an 820-3115 board here.
Bassicly the 16.5v DCin voltage fluctuates between 16v and 12v and no matter what i have tried nothing sorted it
Ive tried new Q7080 and new Q7085 but this didnt change, New U7000, Tested almost all the resistors around the U7000's area. Tested almost all the capacitors around the area.

I noticed lastnight when i have a charging IC installed i can hear a faint ticking coming from somewhere. My only guess is this is the source of the problem or why the voltage is fluctuating.


any thoughts would be apriciated

@smithtony22
could you solve the problem?
have exactly the same board with the same error.

K6_820-2879b_mbp_13_mid2010

Hi guys,

Can I use the U6990 (LPDR/LT3470) IC from another logic board model to solder it on my 820-2879B. I have many A1342 boards that have the LPDR chip on them. Second line of text written on the chip is different. Thanks

late 2011 MBP i5 only works on battery

My macbook pro 13" only works on a charged battery. The MagSafe led is always green. It will not charge the battery. I have checked the white fuse near the battery connector and did an SMC reset. I also replaced the magsafe DC board. Any clues to fix this?

GlassOgnion said:

Hi guys,

Can I use the U6990 (LPDR/LT3470) IC from another logic board model to solder it on my 820-2879B. I have many A1342 boards that have the LPDR chip on them. Second line of text written on the chip is different. Thanks

Click to expand...

check on both schematics for the IC model.. If its the same on both board, you can... sometimes the second lines are factory dates and weeks of production...

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floydturbo said:

My macbook pro 13" only works on a charged battery. The MagSafe led is always green. It will not charge the battery. I have checked the white fuse near the battery connector and did an SMC reset. I also replaced the magsafe DC board. Any clues to fix this?

Click to expand...

well.. there are quite few things that can be...
since your light is green you should have 3.42 v and smc should be fine ( but still can be SDA and SLC lines problems)
Check the charger IC... usually its the most probably IC in those cases... Also there is the charger FET to be checked..
Its needed much more info to be able to help more....
Osciloscope also helps...

GlassOgnion said:

Hi guys,

Can I use the U6990 (LPDR/LT3470) IC from another logic board model to solder it on my 820-2879B. I have many A1342 boards that have the LPDR chip on them. Second line of text written on the chip is different. Thanks

Click to expand...

Yes, as far as i know second line is batch No.

South657

GlassOgnion said:

Hi guys,

Can I use the U6990 (LPDR/LT3470) IC from another logic board model to solder it on my 820-2879B. I have many A1342 boards that have the LPDR chip on them. Second line of text written on the chip is different. Thanks

Click to expand...

dunno if im wrong, but 2879 use a qfn package, while 1342 use a sop layout with normal pins.

dellxps15 said:

dunno if im wrong, but 2879 use a qfn package, while 1342 use a sop layout with normal pins.

Click to expand...

I checked the boardview files of the white unibody A1342 (K87_820-2877_2.4ghz) and the MBP 13" 2010 (K6_820-2879_MBP_13_MID2010) and the 8 pins of the U6990 (LPDR/LT3470) have the same functions so I guess it can be swapped. On the white A1342 unibody 2,26ghz
(K84_820-2567_2.26ghz) U6990 seems physically the same (same package & LPDR written on them) but there are two pins that have differents nets:

-pin 6 & 8 on the A1342 2,26ghz are:

PPVIN_G3H_P3V42G3H but PPDCIN_G3H_OR_PBUS_R on the A1278
all others nets are the same.

U6990 is not a programmed IC so I guess it can be swapped on other boards even if the pins have differents nets. What do you think ?

GlassOgnion said:

I checked the boardview files of the white unibody A1342 (K87_820-2877_2.4ghz) and the MBP 13" 2010 (K6_820-2879_MBP_13_MID2010) and the 8 pins of the U6990 (LPDR/LT3470) have the same functions so I guess it can be swapped. On the white A1342 unibody 2,26ghz
(K84_820-2567_2.26ghz) U6990 seems physically the same (same package & LPDR written on them) but there are two pins that have differents nets:

-pin 6 & 8 on the A1342 2,26ghz are:

PPVIN_G3H_P3V42G3H but PPDCIN_G3H_OR_PBUS_R on the A1278
all others nets are the same.

U6990 is not a programmed IC so I guess it can be swapped on other boards even if the pins have differents nets. What do you think ?

Click to expand...

i wont swap them since the qfn is smaller with smaller pins. and has a gnd pin in the middle too.

A1278 820-3115-b

Hi,
i have this LogicBoard 820-3115 with strange issue, when i plug the power cable fan spin for few second and then stop for few seconds and its keep doing this until i remove the power. Please any one have idea about this issue.

mas119 said:

Hi,
i have this LogicBoard 820-3115 with strange issue, when i plug the power cable fan spin for few second and then stop for few seconds and its keep doing this until i remove the power. Please any one have idea about this issue.

Click to expand...

This can be a LOT of things.....
Can be no power to the processor...... no GPU power... SMC not starting up..
A lot of testing need to be done..

hi again, i have a macbook unibody alluminium 2008. it is alll almost ok, except it drain battery, like 1 light a day. is that normal or i have some problem with it ?

the other macbook 820-2879 u7000 changed for about 5 times give me this pinout:

pins voltage:

1: 8.88volt (should be 0 but dunno why it has that voltage)
2: 15.7 volt
3: 3.86v
4: 3.35v
5: 0.66 volt
6: 3.37volt
7: 0v
8: 9,24volt
9:0 volt
10: 3.37volt
11: 3.37v
12: 3.38volt
13: 3.37v
14: 2.29v
15: 0v
16:1,67v
17: 1.63v
18: 3.04v
19: 5,03v
20:5.02v
21:0v
22: 0v
23: 1.65-2.14v
24: 0.13-0.3v
25: 4.52v
26: 13.99v
27: 15.96v
28: 15.98v


ofcourse on F7040 i have 3.8volt dropping to 1.6 then 3.8volt again and so on. and not 12.5 as it should

already changed the 2 fet for 12.5 volt but still the same.

dellxps15 said:

hi again, i have a macbook unibody alluminium 2008. it is alll almost ok, except it drain battery, like 1 light a day. is that normal or i have some problem with it ?

the other macbook 820-2879 u7000 changed for about 5 times give me this pinout:

pins voltage:

1: 8.88volt (should be 0 but dunno why it has that voltage)
2: 15.7 volt
3: 3.86v
4: 3.35v
5: 0.66 volt
6: 3.37volt
7: 0v
8: 9,24volt
9:0 volt
10: 3.37volt
11: 3.37v
12: 3.38volt
13: 3.37v
14: 2.29v
15: 0v
16:1,67v
17: 1.63v
18: 3.04v
19: 5,03v
20:5.02v
21:0v
22: 0v
23: 1.65-2.14v
24: 0.13-0.3v
25: 4.52v
26: 13.99v
27: 15.96v
28: 15.98v


ofcourse on F7040 i have 3.8volt dropping to 1.6 then 3.8volt again and so on. and not 12.5 as it should

already changed the 2 fet for 12.5 volt but still the same.

Click to expand...

Old batteries do have a high rate of self discharge... it can be just that....
the only way you could really be sure is connecting a power supply while all battery pins are connected but the positive... so you could make a comparison of the amps its draining....
Probably by probing you wont find any answer in this case..
I believe its the battery itself....
Have you tested to fully charge it and remove , wait 3 days and put back to see if it has drained ?