S17+ issue

Dear bitmain support team, hi I have 3 s17+ and all of the sudden all of them have lost one of their chains and due to this issue, they are working with 48th ( they suppose to work with 73th) and after sometime they give me 0 th can you help me solve this issue? Unfortunately i cant send them to you due to coronavirus lockdown. Pleas tell me how can i fix them myself Regards