Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
SMC Issue on MBP 13 - Hardware Troubleshooting Guide
- Thread starter Dadioh
- Start date
- Sort by reaction score
Thanks Dadioh.
Pin 12 on ISL6258 has 0v.
What is the next thing I should check?
Mike
IN a much earlier post Daddiohn posted a schematic for the MBP. I think all late model MB and MBP have similar design, so this explanation is generic:
Around page 60 or so there is a circuit diagram showing Magsafe and Battery power connection. PPDCIN_G3H and PPVBAT_G3H_CONN.
On that same page a G3HOT circuit get its power from either diode pair. The DCIN_G3H (from Magsafe) goes through R6905 (47 Ohm resistor) through the diode, then powers the U6990 voltage regulator that generates the 3.42v signal. Notice that there is "switch" in this logic. The only thing that blocks the DCIN is the SMC bus communication between the SMC IC and the magsafe. Since you have 16.5 already on the board, the SMC IC has allowed the DCIN source to come through (ADAPTER_SENSE_OK signal).
The BATT power goes through a MOSFET (Q7055) whose gate is controlled by the SMC IC (bgate signal), then via a 0.01 Ohm resistor becomes a PPBUS_G3H (~12v) which goes to the other half of the diode I mentioned earlier. Since we know that in a working Mac the system can start on battery alone, the 3.42v must be on all the time via this close loop of BATT power logic.
I believe it is possible to do it off the jumper pads but it is a bit tricky. 3 hands or a prehensile tail come in handy
But yes, I believe these pads act in the same way as the power switch.
My battery is completely dead so unfortunately I have to sort out the Magsafe power problem first. I can find several of these components on the diagram but I'm having a difficult time finding them on the board. Specifically, I can't find the U6990. I assume I am looking for an 8 pin IC of some kind in close proximity to the Magsafe board hookup but I can't seem to locate it. If I could find the L6995 inductor, I may be able to figure it out but I can't locate that either. Can anyone point me in the right direction? Maybe you could use the images of my board above for assistance?
Mike
So I did more teseting. On the fuse next to the magsafe connector I get 18.5V. On the one down by the battery connector i get 16.5v. On the jump pad i am only getting 2.4V. Any ideas...this is on a a1342 (late 2009 macbook unibody) I have attached a pic that shows both fuses, one upper left, one down just right of the so-dimm slot.
Attachments
You should definitely be getting 3.4v or thereabouts. 2.4v suggests that you have a problem with g3hot. Need to troubleshoot that as a starting point. The board can't even begin to boot without that.
Edit. Wait, you said you get 2.x on a working MacBook too? Sounds like your meter is not right. Definitely 3.4v on a working MacBook... Even the old white ones.
Just checked the a1181 again...definitely only 2.2-2.4v...now this is only a partially working a1181...it powers on '(fan and hard drive spin up, sleep light powers on, charges battery) but does not chime or boot...but it gives the exact same reading as the a1342 when i grond the black and put red on one of the two jump pads
From your description it sounds like the power on logic is actually working. The no-boot/no-chime is indicative that the SMC identified a failed power on self-test and thus preventing the CPU from looking into the HD for boot sequence. This is a much broader area to trouble shoot. The SMC receives many signals such as "all secondary power supplies" are generating the needed voltages, SODIMMs are working, DVD/CD drive responds to spin command, etc., etc. I think the 2.4v is OK as the ICs that depends on it have a wide voltage tolerance. I wonder though what it would say with a digital voltmeter. Analog meter may not be calibrated very well unless it is a Simpson 260 or equivalent (lab quality analog meter). I am traveling so I don't have much time reviewing the schematics.
Good to know. It is a fairly cheap analog meter (~$20) from the hardware store. If you get a chance when you get home to review schematics let me know what else to test Board history is just stopped powering on, no liquid damage. I have no RAM installed as I was hoping to hear the beeps/see lights flash...never gets this far.
Board history is just stopped powering on, no liquid damage. I have no RAM installed as I was hoping to hear the beeps/see lights flash...never gets this far.Good to know. It is a fairly cheap analog meter (~$20) from the hardware store. If you get a chance when you get home to review schematics let me know what else to test
Did you try installing the RAM and powering it up with everything connected? There is no on-board RAM in MB or MBP, so that could be the no-chime issue. Also temp sensors, fan, etc. may cause the no-chime.
I had been told by someone that no RAM should equal 3 blinking lights/beeps. I did try it with a 4 gig stick of RAM and still saw nothing....i do have the back speaker and fan coming in the mail this week, also a new topcase (us version keyboard, mine is german). I will test again then.
While bored at work today i checked voltage on all the components with the + on them. They all had readings except for the one in the lower left of my picture attached earlier labeled A7 CH. Any idea if this should have a reading?
Also when i set my multimeter to 50v instead of 10 the g3hot clearly shows 3.X so i think i am definitely fine there. Is there an easy way to check if the battery is getting charge, the a1342 does not have a button to press to see charge/battery status
If it is charging you will see about 12.5V or more to the battery. If not then 12V or possibly a little less than 12V. Also, the magsafe should glow orange if it thinks it is charging.
A1297 - 17" Macbook Pro not charging
Hi All,
Someone pointed me to this forum and thread when i to have a water damaged 17" brand new Macbook Pro. Salvaged from a Mac shop.
At first it didnt boot and the corrosion looked pretty bad on the logic board.
After a cleanup i got it to boot when the Keyboard and battery wasnt plugged in, the Magsafe would only go green a certain way around...and the Apple powered up instantly (no keyboard so no power button)
Stripped it, cleaned it again, replaced keyboard and bought another battery (the old original one came up as NOT CHARGING)
Now it boots, works fantastically but for the life of me will not charge any battery....the magsafe doesnt go orange.... the battery test button, when pressed, flashes one green LED a few times then goes off.
I originally thought i got another dead battery so i planned a trip to the apple store (not close by) to test the batteries...but after reading this thread i might be able to test components to at least rule out a dead battery or charge circuit...even a fuse?!
where is it best to start in the test procedure, if you dont mind me asking and not needing to read through all the posted threads - I have test equipment...soldering etc...but no SMD soldering equipment.....but do have a magnifier and tweezers if i need to desolder/replace?! - i hope i dont need to go that far and its a further deep clean?!
Thanks guys in advance!!
Hi All,
Someone pointed me to this forum and thread when i to have a water damaged 17" brand new Macbook Pro. Salvaged from a Mac shop.
At first it didnt boot and the corrosion looked pretty bad on the logic board.
After a cleanup i got it to boot when the Keyboard and battery wasnt plugged in, the Magsafe would only go green a certain way around...and the Apple powered up instantly (no keyboard so no power button)
Stripped it, cleaned it again, replaced keyboard and bought another battery (the old original one came up as NOT CHARGING)
Now it boots, works fantastically but for the life of me will not charge any battery....the magsafe doesnt go orange.... the battery test button, when pressed, flashes one green LED a few times then goes off.
I originally thought i got another dead battery so i planned a trip to the apple store (not close by) to test the batteries...but after reading this thread i might be able to test components to at least rule out a dead battery or charge circuit...even a fuse?!
where is it best to start in the test procedure, if you dont mind me asking and not needing to read through all the posted threads
- I have test equipment...soldering etc...but no SMD soldering equipment.....but do have a magnifier and tweezers if i need to desolder/replace?! - i hope i dont need to go that far and its a further deep clean?!Thanks guys in advance!!
There a few places but the easiest without posting a picture is to measure the current sensing resistor for the charging circuit. It is fairly large and green in color and located near the connector that goes from the logic board to the battery. You can measure either side of that.
...oh, and i dont want to look as though im trying to hijack the thread...so sorry to the thread starter and can start a new thread if you wish? I just thought i have a similar fault and good to keep this info together?
...oh, and i dont want to look as though im trying to hijack the thread...so sorry to the thread starter and can start a new thread if you wish? I just thought i have a similar fault and good to keep this info together?
No problem. This thread has morphed into a more general thread about Macbook logic board repair. I have a bother thread about Macbook LED backlight repair. I suppose we could create separate threads based on different classes of issues.