Not able to detect any wifi sources

Hi @kangjun ,

As you know water and electronics and electricity are not a good mix.

The impurities in the water causes corrosion and provides circuit paths for the electricity which were not in the tablet's operating design and could damage the components.

First do not turn on your tablet and then you need to remove the battery as soon as possible from the tablet to minimize any further damage.

Then you need to dis-assemble the rest of the tablet and clean all the affected parts using Isopropyl Alcohol 90%+ (available from electronics parts stores) to remove all traces of corrosion and water. Do not use "rubbing alcohol" as in some cases this is only 70% IPA or less, can contain scents and is not as effective. If you do check the label to verify the amount of IPA

Here is a link that describes the process.

Electronics Water Damage

As always with electronics, especially surface mounted PCBs be gentle when handling and especially when brushing away the corrosion. You do not want to remove any components from the board.

Hopefully after you have done all this the tablet might possibly work correctly again.

Here is a link to the ifixit guide(s) for repairing your tablet.

Kindle Paperwhite 3 (7th Gen)

If this process seems too daunting, take your tablet to a reputable, professional mobile phone or electronics 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.