For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
A1278 2012 820-3115-B motherboard reported liquid damage. Board looks visibly OK, no corrosion that I see. I get a green light on the charger, and the fan spins normally for 10-20 seconds, then starts spinning faster. No chime, and no display. Bad SMC perhaps?
I ran this one through another ultrasonic cleaner. It still exhibited the same symptoms, get a green light, and the fan begins spinning faster after 20-30 seconds. I installed it back into the laptop, and miraculously turns on and functions normally, with fan spinning at normal speed. You can mark this one as solved I suppose, though not sure what fixed it. Thank you.