Help Identifying a Component [closed]

I have a USB Tester like this one:

https://www.amazon.com/KCX-KCX-017-Power-Capacity-Tester/dp/B00WBHQJ8W

I have connected it by mistake to a 23 volt power source and the item stopped working. When I opened the item I found that a component was burnt (See the picture below the item marked by the red square):

I found a picture of the same board with the component clearly marked V2MJ (See the picture below):

I've searched the internet and I couldn't find what is this component. Can anyone help me identify this component and if there is a replacement for it?

P.S. The board is marked with a KCX-017-20131222 marking:

closed as off-topic by Nick Alexeev♦Jun 5 '17 at 13:56

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "Questions on the repair of consumer electronics, appliances, or other devices must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design of the device being repaired. See also: Is asking on how to fix a faulty circuit on topic?" – Nick Alexeev
If this question can be reworded to fit the rules in the help center, please edit the question.

• It's most likely a SOT-23 package voltage regulator, considering the location where it is and the designator U4. It has the marking V2MJ, but not sure what the output voltage is – Douwe66 Jun 5 '17 at 13:48
• Give it up and purchase another one. It is only $5.99 USD at the Amazon link. You could pay more than that to just locate, purchase and ship a part to you to solder in. Next time be way more careful how you plug things in. – Michael Karas Jun 5 '17 at 15:04 • This page says it is a AP7313-30SAG-7. Cheap lesson for$6. – StainlessSteelRat Jun 5 '17 at 15:30