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Phillip Garrison
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MBP doesn't power on; Power Pads location on MacBook Pro 17" A1229?

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This MBP 17" Mid-2007 doesn't power on at all - no signs of life. Battery is good/fully charged. I've tried:

- swapping memory for known good memory

- removing internal HD (and internal HD cable) and booting from external drive

- resetting SMC

- using different power adapter, and booting from only battery or only power adapter.

Power cable light is green, and power flows through to an external drive connected via Firewire.

Internal drive is known good (tested in another Macbook).

The only advance problem I had prior to it not powering on at all: the previous night I'd put it to sleep by closing it, connected to power. The next morning it had shut itself down.

I'm down to likely either a bad logic board, or bad keyboard or keyboard cable.

In order to rule out problems with the keyboard or other devices, I'd like to power on using the power pads on the logic board. But, I can't find them on this model.

Where are the power pads on this model Macbook Pro?

Also, any other suggestions for troubleshooting?

Edited by: oldturkey03 ( ) , Richdave ( ) , Phillip Garrison ( )

Anyone? The main thing I'm looking for is the location of the power-on pads on the logic board. Anyone have the service manual for this model, and willing to look it up? (for those who aren't familiar with these, all (most/some?) Macbooks have a pair of pads on the logic board, which when shorted out with a pair of tweezers, powers on the computer, without the keyboard or other power switch attached.

Phillip Garrison,

OK - I finally found the pads myself, after about 45 minutes of staring at the board. The pads on this model are about 1" above the right side of the battery compartment, and 1.5" right of the memory. Labeled "PWR ON". Unfortunately, still no life. So, looks like probably a bad logic board.

Phillip Garrison,

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Richdave
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Check that these parts are OK

Power Cable

Battery Connector

Do you have a multi meter. Can you test the voltages on the I/O power board input? Check this board for damage esp to the solder joints on the power input connector.

UPDATE - Also check the I/O board for fuses, There is likely one on protecting the mag-safe input to the board. Check the battery voltages too to see if it is being charged or not.

Edited by: Richdave ( )

(sorry for lack of formatting - all my line breaks are being ignored) Hi - thanks for the suggestions. Yes, I have a multimeter - see info below. Will need to do some more disassembly to get to the I/O board and those cables. Power does flow through to the firewire ports (was able to power an external drive off the FW port, w/magsafe connected and battery disconnected). Also, power on pads have 3.7V across, with either battery or power cable. Does that tell you anything further? Magsafe light shows green, but the battery is fully charged, and I have no way of discharging it. So, hard to tell if the charging functionality works. I definitely suspect some mechanical break in an electrical connection - it started acting up a couple of days after an airplane trip - in a good case, but still probably jostled around more than usual.

Phillip Garrison,

P.S. disassembled further to get access to the I/O board. 19.5V at the Magsafe input. 19.5V, or 5V (depending on which pins) at the connector to the logic board power cable. Don't see any problems with the solder joints to the power connector. And (see prev. comment), at least some power does seem to be getting to the logic board.

Phillip Garrison,

Just a thought and out of left field but have you reset the PRAM (prob not able to if it doesn't power up though)? Or checked the PRAM battery?

Richdave,

(again, sorry for no formatting; it's ignoring my linebreaks). Thanks to both of you for your persistence. Richdave: no PRAM reset till now, since no power. I thought of the battery, but couldn't find it before. Just found it - 1V. Would this cause this problem?? I reset PRAM by temporarily disconnecting the battery; no change. ABCellars: I did test for continuity on the power cable; forgot to mention that. All clean zeros. Did not think to test for voltages on the logic board end of the cable; can try that. And will examine the logic board connector better (didn't pull it far enough out yet). Also, where is a good place to test 5v on the logic board?

Phillip Garrison,

1V for the PRAM battery does not seem right to me. I'd expect 1.5V or 3V. The PRAM battery pictured HERE has what I interpret as 3V on it but with the preceding characters I am not certain. Cant confirm what it should be just now. Will update if I find it. As per ABC's comment check the +5V at the power cable to start with on the pins mentioned (7 & 8).

Richdave,

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ABCellars
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Remove your battery and unhook your magsafe. Hold down on your power button for 30 seconds. Continue holding down the power button, plug the magsafe into the computer, hold power button for another 10 seconds. Release the power button wait 2 seconds, press the power button as you normally would.

I see you have already found the power on pads. The voltage you mention finding on them should be good. They are on the 3gHot rail which should be 3.3v.

If the little scenario with the power button does not power it on, check the connections of the power cable that run between the left I/O board and the logic board. That cable connection on the logic board tends to come loose and is also known to be a little fickle. If it is loose you can find all the proper voltages on the logic board. But, not have a good enough connection to handle the heavy current draw needed for powering on.

Edited by: ABCellars ( )

Did the power button thing - still no sign of life (magsafe light still showing green). Also removed the logic board far enough to get to the power cable connection under the logic board. While neither end of this cable is a snug fit, there's a good compression fit between the two ends of the cable, and neither end is loose, or going to come loose. Reseated both ends anyway, no change. So - does this look like a bad logic board? If so, I'm ready to ship the thing off for repair (I've found a few places that do component-level repair, with good reviews).

Phillip Garrison,

You have confirmed the 3v rail on the logic board has power with the measurement you got on the power pads. You have not confirmed the 5v rail has power on the motherboard. I believe that the pinout on the power cable you checked earlier is pins 1 & 2 are 3v, pins 7 & 8 are 5v, while the rest are grounds. I'd at least test the logic board side of the power cable for the voltages on it as most of the power regulation is on the left i/o board. I apologize for not mentioning that sooner. I'd test for the voltages off the i/o board power cable connector solder pads for the voltages. The undo the power cable from the logic board and test it for continuity. also inspect the power cable connector on the logic board for burnt or corroded sockets. One last thought, jumping the power on pads will not work if the laptops keyboard is plugged in. Also some times it takes several attempts to get a good short between the pads.

ABCellars,

Hi ABCellars - don't know if you've still been following this; been exchanging comments with Richdave, so I don't know if you get notified on those. I did all the tests you suggested - 5V on pins 7 and 8 at logic board connector, connector solder joints look good. Continuity on power cable is good on all leads. Did discover that the PRAM battery is really low - 1V. Do you know if this can this cause this symptom (no power-on) on this model MBP? Have ordered a new PRAM battery; when that arrives, I'll reassemble and see if there's a change.

Phillip Garrison,

I've followed your dialog with Richdave to stay in the loop. When you attempted to jump the power pads, was the keyboard attached? Try the power pads again using different scenarios. Remember the keyboard/upper case cable can not be attached for the power on pads to work and that the pads have solder on them, making an uneven surface, so it may take several attempts. I would also unattach everything from the motherboard but the left i/o board connections - air port, drives, sensors, etc... Then try jumping the pads with just the magsafe attached, no battery. Try the power on pads with just the battery attached, no magsafe. Even with the voltages on the motherboard, protocol (also Apple Service Manual) says to change out the left i/o board with a MBP giving the symptoms yours does - I've seen it resolve the problem 30%+or - of the time. The idea is to deal with known good parts. The i/o board does play a critical roll in the laptop booting.

ABCellars,

I don't believe the PRAM battery would prevent this from powering on. I'd bet money on that , not my life. I am not sure if this board has it or not. Many Apple laptop logic boards have a "hard" SMC Reset in the form of a set of jumper pads - that are marked accordingly. You may inspect your board for them and if found on your board, with the magsafe attached, jump them as you would the power on pads. I would do this prior to any of the suggestions in my previous comment. I am not sure of the value of your motherboard. It might be best for you to consider Apple's flat rate repair. Apple will replace the logic board (also all other bad parts) for a flat rate fee of $280 if there is no external physical damage or evidence of water damage. 1-800-SOS-APPL.

ABCellars,

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