It depends if the DVD is actually broken, the two most common faults that I have seen, are the lense being damaged, which can sometimes be swapped with one from a similar drive, or the small motor that spins the disc fails, either completely, or makes a rattling sound, that eventually gets worse.
If it is the motor, Find a scrap CD Drive / CD-RW / DVD and swap the stepper motor over. The only problem is undoing the screws, you need a VERY small screwdriver and lots of patience.