One charges only when off ,another have problems

Hello,ive got great problem! I've got two times mini 4! One charges only when off ,another have problems with the touchscreen-sometimes doesn't work! Suspicious u2 and u 15 but not sure! Can someone advise me! Thank you!

Can someone show me picture of the chips on the board,because im not sure which are exactly on mini 4 ,the u2 and u15? Thank you!