I am trying to troubleshoot a friends macbook 2.0 core duo that is acting up. He says it shut down and when he tried rebooting it started but no chime and no screen. The hard drive spins and the fans spin but nothing. I opened it up and found all the connections good, reseated the ram and hard drive, plugged the top case in and tried. Same thing. Googled the symptoms and found a percentage that said the logic board was toast. Some offered options to try. I tried holding the power button to reset the smc, tried to boot and the same thing. I next tried resetting the pram, It boot! We got in and used it like nothing was wrong. I shut it down and but the top case back together, finished with all the screws, turned it over, plugged it in, pushed the power button - same problem - starts but no chime and no screen. Hit the power button holding option-command-r-p and up it boots. What can I do to this to make it normal again for him? Right now it is sitting here on my desk idling now for about an hour without a problem. Is there a pram battery? is this maybe the culprit? I'm rambling now, Help!
Edit: I found that when the screen is repositioned, it goes black, when I closed it to flip it over to install the top case screws, it doesn't reboot. I got it to reboot withe the pram reset only and when I closed the screen (about 45degrees) to see something behind it, it went black.
Is it possible that the cable to the screen is damaged/loose? That would explain the screen problems and the intermittent issues, though I'm not sure why a PRAM reset would fix that. And as for the no chime - that's not a video symptom as far as I know.
Does this MB have any third party RAM? Have you tried taking one stick out and trying that? Checked to make sure the RAM is properly seated?
I assume when you say it starts that you mean the power light comes on? And do you hear any fan noise or HD noise (when the screen is black, with no startup chime)
You might want to check this KB article out - particularly step 6 in the built-in displays section.
When it starts without the chime or screen, it just site there, doesn't boot to anything, goes no further. Fans spin and hard drive/optical drives are active.
When it starts holding the 4 buttons to reset the pram, it actually boots and is usable like nothing is wrong with it.
It has ram I have never heard of and sometimes I reset the pram I get 3 beeps and the power light flashes 3 times repeatedly.
What happens if you boot it from a cold shutdown state using 'safe boot bode'??
ie: hold down the shift key when booting at least until you see the spinning gear.
I will try that later thanks and let you know
Quote:
Originally Posted by Lars
No chime/no video on boot means the unit hasn't passed the POST on startup - consistent with a bad logic board.
but would a bad logic board boot and run starting it with a pram reset? I hold the 4 keys down, it chimes, restarts, chimes, restarts and I let go of the keys and it boots and runs normal. This makes me hope it's just pram battery or ram (which I don't have spare to test) thanks.
You can try swapping the battery on the board if you can even get a replacement battery (it's no standard battery; Apple doesn't even sell the battery on its own to us technicians) and re-test; and yes, bad logic boards (and bad other parts) can be bypassed under certain conditions, but that doesn't mean the part isn't broken.
__________________ ACMT Mac mini (Mid 2011) 2.7 GHz i7, 8GB RAM, Crucial M4 256GB SSD + 500GB + 1TB FW800 OWC Mercury Elite Pro mini iPhone 4S • iPod nano 8GB • Sound System Audio Engine A2 • Display UltraSharp U2412M 24"
If you boot via using the pram command, the go under the apple/about this mac/more info/diagnostics, you will likely see some kind of ROM memory error. Logic board related, and sounds like what eventually killed my last tibook.
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