Galaxy S7 930F cannot unlock sim and IMEI null

Dear all, I bought a defective Samsung S7 930F mobile which I would like to repair.

The phone is working in all its functions except :

- Cannot unlock SIM card when I insert it

-IMEI shows 000000000000000, IMEISV 01

- Battery drains fast (approx. 10%/hour)

If I insert a working SIM card, the card is detected, but once I insert my PIN I get the message 'SIM PIN Operation failed'. So I am unable to unlock my phone. Sometimes it is stuck endless unlocking the phone.

I already tried: Factory reset; cleaning the whole logic board with isopropanol

I think all this problems are related to one root cause. It should be a hardware problem.

Do you know which IC is responsible on the board for getting the IMEI and unlocking the SIM card ? I might try to re-solder the pins.

I would really appreciate your help