Liquid damage BUT working only on Power Source [WEIRD SOLUTION FOUND]

Dear all, somewhere in November 2013 i spilled some water on my Macbook Pro 15" Early 2011. Magically enough, the Macbook Pro still works BUT it has a weird issue. Although the battery's condition is perfect and recognized and charged by the system as in a normal Macbook, the liquid (as you see in the picture attached) has caused a problem regarding the power supply: every time I unplug it from the power source the macbook shuts down, like it's not able to recognize that it has a battery inside ONLY when i unplug the power cable. The even weirder thing is that once a while it DOES recognizes the battery when i unplug the power source and i can use it like a normal Macbook Pro. (The battery charges normally afterwards as i said and also ,in general, when the power source is connected). The only solution that the Apple Store suggests is the insanely stupid and costly change of the whole motherboard which is, of course, out of discussion since the Macbook Pro still works fine and besides that I could just go for a new one. Of course, I attach the picture of the liquid damage not expecting some magical fix BUT maybe a recommendation/solution or some advice from someone with a similar or the same rare "problem". Also sometimes after I unplug the power source and the macbook shuts down, i have to open the case (unscrew the screws etc.) and unplug the battery connector for a couple of minutes and then plug it in back again. After that, the power source is magically recognized again and i can boot up normally

SOLUTION FOUND: I tried my old Macbook Pro charger (2007 model) and it works fine! The power (in watts) from the old macbook is way less than the adaptor of the problematic macbook.