iPhone 6 keeps vibrating after answering call

Hello everyone,

iPhone 6 keeps vibrating after answering the call, time counts on screen and no sound can be heard on speaker and on earpiece, also other person wont hear you.

In very rare case the call is successful and everything works fine, but most of time problem occurs.

I know it is logic board problem.

I read that it could be Qualcomm WTR1625L RF transceiver, but maybe anyone fixed this problem and can tell more about possible solutions maybe it is not RF Transceiver? Thanks all, hope I will get help here!

P.s.

No water damage.