Hi,
It seems as though the display has been damaged by the water (hopefully that’s all) and it may need to be replaced.
The impurities in the water causes corrosion and provides circuit paths for the electricity which were not in the phone's operating design and could damage the components. The corrosion starts immediately and is ongoing until it is completely cleaned away.
Rice does not fix the problems caused by corrosion Rice is for dinner, not repair
First do not try to charge or to turn on your phone and then remove the battery as soon as possible from the phone to minimize any further damage.
Then you need to dis-assemble the rest of the phone and clean all the affected parts using Isopropyl Alcohol 99%+ (available at electronics parts stores) to remove all traces of corrosion and water. If possible do not use "rubbing alcohol" as in some cases this is only 70% IPA or less, can contain additives and is not as effective. If you do have to use it check the label to verify the amount of IPA. The higher the percentage of IPA the better
Here is a link that describes the process. Electronics Water Damage
As always with electronics, especially surface mounted pcb be gentle when handling and especially when brushing away the corrosion. You do not want to remove any components from the board. Remove the shields that may be covering some components as the water may have got in under there. The ends of any flex cables and their connectors need to be cleaned as well
Hopefully after you have done all this the phone might possibly work correctly again.
Here is a link to a teardown video for the phone which may help.
If cleaning the phone with IPA doesn’t completely fix the problem then initially as a DIY repair all you can do is to replace the display assembly and see if that is all that is wrong with it. Replacement assemblies (supplier example only to show cost) are available online. Just search for Samsung A21s LCD display replacement to find suppliers that suit you best.
If this process seems too daunting, take your phone to a reputable, professional phone repair service, experienced in liquid damage repair and ask for a quote for a repair. If you decide to do this, do it sooner than later.
4 Comments
Same thing happened with my A21s. I dropped my phone in water picked it up and dried it off thought it would be fine. After just 1 minute the corner of the display near the speaker started to become cloudy. I thought I could dry it up with a heat gun but it was too late. Somehow water got in between the lcd layers. And it continued to spread and do even more damage causing many rows of dead pixels. Seems that the display is unfixable amd needs replacement.
by HighVoltageMadness2300
Display is not working
by army status
@armystatus
See the answers below
by jayeff
My phone was submerged in the water, screen has purple filter
by MT Tanim