Mac won't boot at all

C

colin_m

Registered
Hi,

I've posted this on another couple of forums but struggling to find any advice. Hopefully someone on here can help.

Couple of days ago my macbook pro (A1226) simply wouldn't turn on at all. Running of the battery and pressing the power button would return nothing, running of the mains would return a clicking noise from around the io board.

The logic board is 6 months old and I replaced the IO board myself 5 months ago. I've tried the old IO board in it and still no luck so it's not that.

I thought it was a complete brick until last night I hit the button and it started up fine. I restarted a couple times and all was looking good for around 20 mins when it suddenly lost power again. I now can't get it to turn back on.

Due to trying 2 io boards and the fact that it's started again I'm thinking it can't be the logic board....anyone got any ideas as to what it can be?
 
colin_m said:
The logic board is 6 months old and I replaced the IO board myself 5 months ago. I've tried the old IO board in it and still no luck so it's not that.
Click to expand...

So what was the point in replacing the i/o board 5 months ago then if it wasn't broke?
 
ha, guess thats a good question, quite a long story but basically the backlight died and so I took it to a company that claimed to be an apple authorised tech, they weren't authorised at all (not naming names but they are the primary independant retailer in Scotland!! ie very well known!!) and so because of that my warranty is buggered. I've therefore had to carry out repairs myself using advice from forums. Managed to work out it was the io board at fault and replaced it, it would start up the machine but just have no backlight.

So..the old io board should have started up the machine but just with no backlight.

Hope that makes some sense.

Is there a part of the machine that deals with the power apart from the io board?
 
From my experience, this is most likely the logic board. I can't tell by the model number you posted (it covers many models of the mpb), what processor is this machine running?
 
It was the santa rosa model, would this have changed when the logic board was replaced and if so is there a way to find out what it is now without turning it on?


And please excuse my ignorance but would it not be that if the logic board was faulty it would stay faulty and not come back to life for 20 mins?
 
If the problem is related to overheating, then you may get it to work (sometimes, and for short durations)
 
So it does sound like it could be an overheating issue?

Is the component that would prevent the computer turning on due to an overheating issue be separate from the logic board?
 
If overheating is one issue, then it could be something simple, like improperly applied heat-sink compound (too much, not enough, etc)

Is the 'clicking' noise just a single click, or repeating/rhythmic clicking?
 
The clicking when attached to the mains is a double click (sort of on/off) on a quick press of the button but sounds just like a car indicator (continuous) if you hold the button.

If running off the battery it will on/off click once then not again unless you leave it for a minute.

I didn't mention before but it's a late 07 model, is it possible that any heat sink compound could have such an immediate impact after such a time?
 
Last night I thought I would take out the logic board to see if there was any obvious damage underneath, The thermal paste was spilling off the "chips" and onto the green surround, I scraped most of the overspill off, blew of any dust I could see and put it back together again. I didn't have any real problems with all of this but after I put it back together and plugged in the magsafe it starts making the continuous clicking noise mentioned earlier but without the power button being pressed.

Any ideas what can cause this?
 
Might help to loosen the top case, and try the locate where that clicking is coming from. Do both fans turn freely?
 
The clicking is coming from the IO board where the magsafe connector is. The fans can turn freely and it does the same with the HD connected or not. The top case is not attached.
 
The i/o board is also the sound board. The clicking could just be something to do with sound. I suppose you could unplug the speakers from the i/o board and see if the clicking stops, but it might not make a difference. But regardless, all you can do is disconnect everything until it is literally i/o board, logic board, RAM, fans, and AC power then see what happens. If still the same thing try pulling the RAM and see if the logic board even signals that there isn't RAM installed. But looks like this machine has already been through a spill. Might have corroded on the board.
 
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