Note 6 Pro - camera problem -pls hlp

[gpsparth]

my redmi note 6 pro suddenly gives the error " camera can't connect"

from hardware test, i got problem with "BACK BOTTOM CAMERA"

when i disconnected(blocked by tape) back bottom camera.

After this step camera apps works without error.

1. Front cameras working well
2. without back bottom camera the quality is worst and no flash (but Torch works)

How to check the problem is in camera or PCB? how to check PCB for problem.

pls guide to check and repair.

if someone provide check points with normal value, i can mange to check since i m not mobile tech.

thank you
waiting for your reply.