ps3 Repair advice Blu ray drive problem ,ive tried full new drive and laser.?

Hi i wonder if anyone can help me please , basically sony ps3 (model :- CECHG03 ) not loading games , ive tried a fully working drive from another fully working playstation 3 , but the console still wont load games , ive also tried a new working laser in the same drive , still no luck

So i assume its a different problem , can anyone help , or point me in the right direction to help solve this issue.

I'm told that this is a common problem.

TIA.