Sometimes in a small bedroom between closets, doors and windows there aren't a lot of good options to mount a TV that works with the furniture layout. This was the case for me in the small bedroom I'm using as a guest room and home office. I spent a lot of time trying to come up with solutions. Everything from ceiling mounts and even a drop down mechanism from the attic but they all seemed overly complex. In the end I decided to try to mount the TV on the sliding hollow core closet doors and it worked out pretty well.
Disclaimer
This mounting technique isn't the most ideal. Even though manufacturers of TV mounts provide a warranty against damage to a TV if the mount doesn't hold, none of the ones I contacted for advice will honor the warranty in this type of mounting. You need to make sure the door is in good condition and the track hardware is in good shape. Still I wouldn't recommend doing this with a very heavy or expensive TV or in a room children have access to. It has been working fine for me for over 3 years with a 32" TV but you understand if you do this you do it at your own risk.About Hollow Core Doors
Hollow core doors are constructed from a thin veneer face mounted to a thin frame and the middle section is usually filled with some sort of material to keep the veneer from caving in. Sometimes cardboard honeycomb is used as the fill. The veneer and fill isn't strong enough to support the weight of a TV and mount.
Other considerations
Since the door slides I think it's best to pick a smaller, lighter TV. An LED TV with a width that's less than the width of the door will work best in my opinion.Mounting a TV to a Hollow Core Door
First we'll need to get a piece of lumber that is cut to the exact width of the hollow core sliding door. In my case it was 36".The width of the board should be a few inches wider than what you'll need to attach the mount. You want to have the screws at least couple of inches away from the edge of the board to prevent splitting.
The thickness of the wood should be at least 1". 1-1/2" would be better. You can use framing lumber but you may want to go with something that has a nicer appearance such as pine boards marked S4S (surfaced 4 sides.) A 5/4 x 6 board worked for my mount.
Start by securing the board to the hollow core door and making sure it's level. Drill pilot holes and countersinks into the board and door frame to prevent splitting while driving the screws in. I used #8 2-1/2" coarse thread bugle head wood screws that I found at my local Home Depot. You want to make sure your screws will drive in at least an inch through the door frame but not so long that they poke out the back. If you use a thicker piece of lumber you may want to get longer screws. I used 5 screws on each side spaced about 1" apart. If you're using a wider board I would recommend using more screws.
Once you have the board mounted, you may want to take the time to paint or stain the board so it matches the door.
Next you'll mount the TV mount to the board you just attached to the door. Drill pilot holes and use the appropriate lag screws. I was able to use the lag screws that came with the mount because they weren't so long that they would go through the board and door.
Before I mounted my TV I waited to make sure the heavy mount was secure enough to the door. It was so then I mounted the TV. Follow the instructions for your particular mount to get the TV attached.
Cable management will be a it of an issue. Leave some slack in the cables so you can slide the door open and closed as needed. Attach the cables around the top of the door trim to help keep it out of the way when accessing the closet.
This isn't the most ideal solution but it's been working out pretty good for me. The doors still function properly for me to access my closet and even with sliding the doors, tilting and turning the TV it's been very secure.
