aha ok now i understand, you only put in your controller board, have you tried using the recovery menu? i know there is one option there that people say have made their ps3 to read discs again, gonna look up which option.
Edit: ok, in the recover menu have you tried option 3? REMEMBER 3 ANY ELSE CAN MAKE ALL DATA ON HDD TO BE WIPED!
that might fix it worth a try if you haven't tried.
and also make sure sensors under the Blu-ray drive are making contact with the base of the system, that can also make the drive not read discs.