Hi!
Okay, it does sound like that the replacement laser is faulty. But, you also got the open tray error right? Did this happened after you replaced the laser?
What you can do is the following:
* get a new xbox 360 drive and replace the PCB of that one with yours. Test if it works now.
* You can also replace the laser deck. This is easier and you’ll replace multiple components at once. But the sensor (which can be faulty) will not be replaced….
I would recommend to get a new drive, if this is not possible or too expensive, then replace the laser deck and try to see what happens.
In the worst case, there is something wrong with the PCB, but lets try that first.
Please let us know how it goes!