Hi motechman;
The number is on the side you are looking at, they move it around from year to year it will be on the left hand side from the middle just up
from the ram and as far over to the fan connector and up around the edge of the board by the fan wires. It will be on it for sure.
You need to replace the keyboard so you can do a pram reset you can not do it without that key then that should sort out the fan and
other things that might be wrong.
Also changing the battery would be a good idea they are not much. And if you want to speed things up go for SSD drive.
Regards
south657
The keyboard has now been replaced. I reset the SMC and the unit seems to boot normally now. However I can't move the mouse pointer and the keyboard seems dead. Before I received the new keyboard I tried to boot an Apple Hardware Tools disk and noticed then the mouse & keyboard were dead. Could not boot AHT CD.
I could plug in externals (mouse, keyb) and then login. I assumed there was something in the SMC that was affecting the keyboard controller and decided to wait until the new keyboard arrived before messing around with the machine anymore.
I'm highly confident I was able to reset the SMC based on the response of the magsafe LED when I hold the control, shift and option keys down upon booting.
With the Mac powered off, the magsafe shows orange (battery is around 95%). No change to that if I just press the power button, which just boots to the login dialog screen. If I hold the shift-option-control keys and press the power button, the magsafe turns green immediately upon releasing the power button and returns to orange 5 - 10 seconds later, and the mac does not start. It doesn't matter if I hold the power button longer; nothing happens until I release it. I can release it after releasing the shift-option-control keys too, no change (as long as I pressed the power button with those keys down it seems to do an SMC reset based on the magsafe LED).
This tells me the keyboard is connected and working, at least in terms of the SMC reset sequence. With the old keyboard in place startup didn't work this way; no matter what keys I held the system always tried to start.
Now that I've done the SMC reset the system starts normally from a single press of the power switch and seems to run normally if I use an external mouse and keyboard. I restored the MacBookPro7,1.plist file that I removed to keep the system from wasting cpu cycles spinning it's wheels, hoping to get the fans restored to normal operation. It didn't work, the system's performance was terrible after rebooting, so I removed the file again. Resetting the SMC did not resolve that issue.
I tried to start the AHT by holding the D key down during boot. It failed if holding the MBP keyboard D key but succeeded if I held the D key on the USB keyboard. External mouse worked fine to select language, and remained OK UNTIL the hardware probe was started and then the mouse froze. That'a as far into the AHT that I could get. Waited for 10 minutes but machine never responded.
I pulled the back cover off and reinspected the connectors for the keyboard and trackpad. They looked OK and were well seated.
I'm at a loss on what to check next here folks. I still haven't been able to find a schematic or layout for my 820-2879B logic board either.