Is my screen going bad or is it my motherboard

[Android Central Question]

Last Sunday i dropped My LG V-20 phone in water. I did have a case on it and it did not get too wet. I did what every one says to do and put it in rice. It worked before I did that. But after a few hours the screen did not come up. The ph would power on but the screen would stay dark. So on Monday I called around to the phone repair shops in town. That was when I found out not to put it in rice but to get it all dried and cleaned up on the inside. And how much they each would charge to water damage restore it. So I took it apart and used rubbing alcohol to clean up the terminals on all the connectors for the screen and mother board. I let it sit before I put it back together. Once together I tried to see if it would work. And it did. It has worked fine now for the rest of the week. But now last night I started getting fuzzy lines across the screen. The 1st time to took over almost entire screen and I was not able to do anything with my phone. It would not even turn off. I had to pull the battery out to get it to turn off and rest it. And since that 1st time it has happened a few more times. But some of them cleared off with out having to pull the battery.
I am hoping you might be able to tell me if it is the screen going out or if it is the mother board

 

[Rukbat]

i dropped My LG V-20 phone in water. I did have a case on it and it did not get too wet. I did what every one says to do and put it in rice.

"What everyone says to do" is wrong - that's step 1 in killing the phone.

So I took it apart and used rubbing alcohol to clean up the terminals on all the connectors for the screen and mother board.

That was about 24 hours too late to do any good.

I am hoping you might be able to tell me if it is the screen going out or if it is the mother board

More likely the motherboard, but the screen can be gone too.

Two things you NEVER do with a wet phone, 1) don't immediately (not in 2 minutes, now) soak it thoroughly in alcohol, and if you can take it apart, soak every piece individually in alcohol and 2) charge it until it's completely cleaned off and dry.

But, since you took the phone apart with no experience, you could also have snapped components that are almost too small to see, snapped hair-thin wires, burned out lands, carbonized boards. About the only usable parts of the phone now are non-metallic parts of the case. But replacing all the rest, even if you could do it yourself, would cost more than a new phone, so throw the pieces out and buy a new phone.

And read Oh, no! My Phone got Wet! for the next time you drop a phone in water. They can be saved, you just did it wrong. (Putting the phone in rice gets rid of all the water and concentrates all the impurities that were in the water, eating away at the phone if the humidity is anywhere above about 5%. By the next day, it was well on its way to the town dump.