I just recently picked up a 13" macbook off craigslist. The seller stated that the only issue was bad ram modules, took it back to the computer repair shop that i work at, popped in some ddr2 ram, all i got was the rapid blinking sleep led on the front. to my understanding, that signifies bad/no ram. I have verified the ram I used works in another macbook. took apart the system to find there was a bit of spill damage on the motherboard. I went and cleaned up the whole board and ram sockets using MEK(chemical solvent) and a soft fine bristle toothbrush. Now the board looks like its in perfect condition, except it still won't recognize any ram modules at all. I have tried just one stick in each slot, and exact pairs and all i get in the blinking sleep light. After that, I attempted to reflow both the northbridge and southbridge chips with a dark IR reflow station we have at work. still the same issue. Im getting the feeling that there might be a dead component somewhere between the ram sockets and the path they follow to the NB. at this point i feel like im at a loss with this system.
i dont know the exact model(left laptop at work to hide from wife). I know its a A1181, 2.16ghz core 2 duo, came with a 160gb drive, 13" screen, plastic body. the number on the board identified it as a 820-2213-A. If anyone out there with the schematics would be able to tell me what components i should focus on, i would be forever grateful....
EDIT: turns out after another MEK bath in a DIY "ultrasonic cleaner", and using a different type of flux under the chip, and a northbridge reflow has fixed it. figured id post this for documentation sake.
LONG STORY SHORT:
if a 13" '07 macbook 2.16ghz core 2 duo always has rapid blinking sleep light and doesnt turn on, even though the ram is in fully.... It might need a northbridge reflow.