Thanks for your kind help guys. I have already paid Bitmain to send it back to me. Now I will follow your advice and send it to someone who can fix it.
I am just disappointed with Bitmain.
Good luck !
At least with an independent repairer you will probably just send the faulty hashboard and keep the rest of your S19 with you.
Anyway, we probably have here one more proof of Bitmain's consistency in exaggerating with the guarantee terms and customer support..