CD tray does not open completely, like it stops half way open.

Quite commonly the tray will only open a fraction of an inch. Is this the case or does it really open half way? If it opens half way you may be able to pull it the rest of the way. You might find it opens properly if the drive is upside down or on its side. In any case, you will have to open it up to find what’s jamming it.

Opening only a fraction of an inch is normally caused by a peg which locates in a hole to lock the drawer shut. The mechanism should withdraw the peg before starting to move the tray but sometimes through wear the peg won’t be removed soon enough and then gets jammed in its hole. Once you can see the peg and the hole and understand their operation you can often cure it by filing either the peg or the hole (or both) to give it a bit more clearance.

If something else is jamming you should be able to see it when you open up the drive. Take great care not to touch the lens as it’s suspended on a set of fine wires to allow its position to be micro-manipulated in order to follow and focus on the track. If it’s already broken, for example by being hit by a foreign object, then that could be what’s jamming it. Or if you have small children around maybe one of them introduced a foreign object into the tray.

By all means have a go - you will learn something and have fun in the process and you may even save a drive from landfill, but if it comes to it, a new drive is not expensive and is easy to fit.