Hello,we have received the TV board card you sent to us, but we still can't start the TV after we replace it. Is there anything to be paid attention to when replacing the motherboard by ourselves or are there any operation instructions or better solutions? Or can we send two TV sets back to Germany, and you help us detect and repair them? P.S. We can't download the catalogue of LOEWE products you sent to me. It is showing that external sharing is forbidden. Sincerely looking forward to your reply!