Broken PS2 Slim disc drive?

I live near a game store that occasionally sells broken consoles for around $5, and I'll buy them, repair them, and either sell or keep them. A while back I picked up a PS2 slim model (SCPH-75001) with a broken disc drive. I thought it was just a faulty laser, which I know is common in fat models (my fat had a bad laser at one point). I had it sitting there for quite a while (mainly because I didn't have a power supply and I was too lazy to get one), and today I found a power supply for a good price (at the same place even) and got to work on it. When I turned it on, I noticed something bizarre, the drive did absolutely nothing. I looked into it and found that the sensor for the drive cover can go bad easily. I read to add a lot of pressure to the rear sensor, while simultaneously pressing the front one. Nothing. Then I did some more reading and to summarize what I found... If the laser is bad, the motor won't spin, but if the motor is bad, the laser won't do anything. That left me VERY confused, it could be anything. I even read that it could be the pot causing it (i'd rather not mess with that). If anyone has any suggestions on what I can do, please tell, I would appreciate it.