if its reading discs the ribbon cable is fine. If its only an eject issue it's most likely an issue with the mechanical parts inside the drive or if it makes no attempt to eject the disc (blue flashing light or no beeping with no disc in) it could be your eject button is broken/misaligned try ejecting from the software (PS Menu).
As for fixing the clip, if the other PS3 is the same model the lid for the clip should fit, it just connects on a hinge. you can swap them over easily enough. If the socket part of the clip has broken off your best bet would be to take the socket off the spare PS3, connect it to the end of the ribbon cable and solder the individual pins on the bottom of the socket to the connections on the board where the old clip was with short lengths of wire. Like individual wires from an old IDE ribbon cable.