MacBook won't boot, power issue?

Hi all,

I am having a problem with my MacBook Pro A1151. When I turn it on, the fans and hard drive spin up, but that is all. No chime, and the dvd drive makes no sound. The light on the front of the computer comes on, but it's a little dim.

Here's what I've tried so far, each time, I've gotten no change:

-Reset PMU, SMC, and PRAM

-Tried booting with no ram, then with a single known working stick in one ram slot, then the other slot

-Unplugged optical drive, hard drive, wireless card

One thing is, I don't have the 85 watt MagSafe power cable, just the 60 watt. But the computer has run fine in the past with the 60 watt connector. And the battery works fine, so could this really be an issue?


I have some hope! After cleaning the board with vinegar, I got more response when I turned the computer on. Dvd drive clicked, screen flashed. I also got a sizzling noise. It occured on the board in one spot, but MAINLY it occured on the power board. When I have the computer battery plugged in, and I plug in the DC-board, it starts making a tiny sizzling sound. It starts making that noise as soon as I plug in the ribbon type cable. I'm really thinking the power board is bad (it seems like the board must be present, even when only the battery is being used to power the computer). Sometimes when I turn it on, nothing happens, or the fans vary their speed up and down, or the screen flickers. So here's what I'm going to get:

1. DC power board

2. 85W MagSafe

3. DC board cables

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Nice, clean the board with ISP alcohol - 90% or better. Did this have a liquid spill - not mentioned? Don't forget to reapply thermal compound/paste when you reseat the heatsink. I use generic stuff while testing and Arctic Silver 5 after I am satisfied things are good. Did you ever acquire the info from the other MBP?


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When you try to boot without RAM does the system beep or does the light on the front of the computer blink? Let you battery charge to 20% then try powering it on. Please let us know the results of both things. What are the last 3 characters of your serial number, please?


You have a motherboard/logic board issue if during POST/boot your computer is not screaming "Huston we have a problem." by beeping and/or the front light flashing, when no RAM is installed.


I have charged the battery almost completely. When I boot the computer without the ram, the white light on the front of the machine comes on and stays on without blinking. Same result as when I boot the machine with ram (just a single stick). The computer has never made any beeps at all. The last three digits of my serial number are VTG.


That's kind of what I feared. Is there anything I can do? Disasseble the computer, clean the board? It's like half the board has power...the fans and hard drive get juice, but not much else, it seems like.


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Your comments constituted an answer, so I changed it to one.

I am sorry Evan, your motherboard/logic board needs repair or replacement. When they don't acknowledge missing one of the most fundamental hardware parts there is serious problems - Not really much different than you not noticing you are missing your eyes.

Hang on a sec, ONE more thing. I have another MacBook Pro that works great. When I try to boot that one with no ram, I get the same result as this MacBook: NO beeps of any kind, it stays silent as well. So I don't think I'm going to give up quite yet. I'm going to clean the board. I'll keep things posted.

The standard is no beeps and/or flashing of the front light. Some versions of the MacBook and MBP beep and others flash the front light with no RAM. If you read my initial comment, I mentioned to look for either and/or both. I don't want my answer to be correct here. I also don't want to give you "rose colored glasses" either.

No, I understand. I was clinging to a shred of hope, I guess. I guess my other MacBook is just odd in that it neither beeps nor flashes the front light when there's no ram and it's booted. Interesting.



If the battery is charged, your machine will run just fine off of the 65W power adapter. Problems come up when the battery get depleted. Of course this may not be your problem at all. Charge it up and see if it will boot from the optical drive, "C" key on start up with the disk inserted. Go to the second screen pull down menu to Utilities, Disk Utility and see if you can repair your hard drive. Let us know your results and we can proceed.


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Unfortunately, the optical drive is quite dead, and so is the screen. The optical drive won't accept a disk, and nothing happens when I hold down the "C" key while booting.

Contrary to nomodos statement, you have not damaged anything using the 65 watt adapter. Don't worry about that. ABCellers is correct. Please answer his questions.


You probably messed up your power board running off the 60W. This model requires the 85W.


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The computer belonged to a friend who had no idea, I guess. Is it possible the whole logic board is fried because they used a 65 watt charger instead? I've never heard of that before.

You will not ruin the power board and/or logic board with the 65 watt magsafe. It puts out less voltage and current than the 85 watt. Components on the laptop are not hurt by not enough. If anything would have been overworked/damaged it would be the magsafe. The 65 watt magsafe puts out enough to let a MBP run, though normally it needs the battery to be charged 15 - 20% to power it on.

I'll get an 85W charger. But were you suggesting I get a new power board as well?

I am not suggesting you buy anything and/or that anything is damaged. If you battery will charge to 20% or more you may not need anything.


to determine if its adapter issue try to replace your 60w to 85w and try to turn on w/o the battery, if still same problem try to insert your battery and plugin the adapter 60w or 85w (don't turn on) it must have charging indicator and light indicator in the battery is blinking. if is charging, both 60w and 85w are good. try booting w/o the ram check if the power light indicator goes blinking. pls let me know the result.


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Well, I don't have an 85w adapter currently, but I can confirm that when I plug the 60w magsafe charger in, the light on the charger turns amber and the lights on the battery flash, indicating that it is charging. The battery charges even if there is no ram. I've tried booting with and without ram, same result each time, nothing.


I have the same problem. I think it is SLEEP mode issue as mine started working after a while and now "dead" again after i put it to standby.

Apple repair could not find fault.


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