Hi, A friend asked me to take a look at his late 2011 MBP, i7, 8GB. It does not recognize the charger. I ran the Apple Hardware Test (several times) and got this error: 4SNS/1/40000001: VP0R-0.000 This seems to have to to with a voltage/sensor/power buss issue... If I remove the bottom plate and disconnect the battery and (sometimes) remove one of the memory sticks, the charger is instantly recognized... So I was able to recharge the battery and it seemed to work fine. But once the charger is disconnected it becomes unrecognizable again. I've tried the usual stuff, NVRAM and SMC resets. I have tried three different chargers that work on other machines. He says he only wants to fix this if the fix is relatively cheap. If he has to buy a whole new logic board then he'd prefer to sell it for parts and buy new. Any ideas? Thanks.