new ps3 blu ray drive still wont pull in the disc

so i was having problems with my ps3 not reading blu ray discs so i decided to take it apart, i did and put it back together all alighned properly as ive watched so many vids now its crazy, any way it wouldnt pull the disc at all, in fact it would not do anything not even if i took the top off, i dont see the laser or any type of movement with the top of and switching ps3 on wich i9m sure you should, anyway i thought the drive must be busted so i brought one on ebay for 36 pounds, took the pcb board of my old one put on new one and same problem it wont take the damn disc

any ideas guys, i was thinking the cable?