I've just replaced the logic board of my A1211 MBP.
The new part works just fine, but... sometimes my mbp doesn't boot at all !

When I press the power button, the superdrive spins, the hdd spins, the fans spins, but the screen remains black and I don't hear any sound from the laptop. I tried almost anything I know: with battery, without battery, with ac, without ac, swapping ram modules and removing one of them, but nothing seems to solve the problem. When the laptop doesn't boot, it quickly becomes very hot.
Sometimes it boots normally, and really fast as usual and as it was before replacing the old damaged logic board (video chip or memory, causing terrible artifacts on screen). Just after replacing the logic board I've reinstalled a OS X.

Don't kwow how to proceed now. Any suggestion ?

Thank you.
Max

Generally if you turn it on and nothing comes up on the screen like that it is going to be a logic board problem. You may want to go back in and make sure no temperature sensors are getting pinched and that you have a good even layer of thermal compound in between the heat sink and board.

The laptop generally works good, only sometimes I see this problem with a cold boot: this happens once every 5 or 6 cold boots.
I don't think it's a temperature sensor problem. I installed the Temperature Monitor Widget, and all temperatures are reported correctly, as they were when my previous logic board was working correcly: cpu never goes above 55° C in normal use (with DVD playing, web browsing with flash movie ecc).
As I stated before, the laptop don't present this boot problem every time I try to turn it on.
I'm not a Mac expert, and I don't know if I have to do something special after replacing the logic board, especially in software. For example, System Profiler reports the logic board serial number as "SystemSerialNumb", which is a little strange to me.
Should I do something else other than fisically replacing the board ?

Thank you.

You can try resetting the PRAM. To do this, shutdown the machine, unplug it, take out the battery, and hold down the power button for 10 seconds, then plug it back in and turn it on.

The problem is still present. Now is becoming even worse: most of the time the laptop doesn't boot. When it boots, all the temperatures are good. Tried to boot with and without battery, with no success.
I think the logic board is still covered by warranty (Order # 121547), am I right ? If yes, how can I have a replacement or a refund ?

You can call or email our customer support department.