Water Damage and Makes a noise when the battery is connected

I unfortunately dropped my gopro hero 4 in water without the case on because i was getting ready to film. Anyway it was completely submerged for 4-5 seconds. I took out the battery and card and set it in rice for 3 days. When i tried to turn it on i put in the battery and it makes a little buzzing noise. I think that it may be the motherboard but, i want to make sure before i spend 150 on the part. Any ideas? sisterboard or battery compartment?