Boots only after multiple attempts

I dropped a coffee in the machine. Battery sub-system "died", it can't hold power either with Apple's battery or an OEM battery. The machine works normally when connected to power, but it has difficulty to boot. Here's what happens: I press the power button, little front light flashes, then nothing. I unplug/replug the power cord (I'm not sure why I do that, but it seems to help). Re-try. After five or six attempts the drive will start. I keep the power button pressed until the screen lights up. Only then I leave the button. Most times I'm good to go. A few times the machine lost power when I stopped pressing the power button. In such cases the next attempt worked. I took the machine to Apple service. They told me that it cannot be re-paired. However the machine has been working reliably for some months now if I follow this little ritual. Any ideas? Thanks!