I know this is an old thread and the OP is probably long gone, but I found the photos quite helpful in swapping out my DNX7100 optical drive so I thought I would add to it to help anyone else in the same boat.
The original optical drive DVS-8530V has been discontinued. Kenwood's official parts source, Pacific Parts, indicates the replacement part number is 880A69-2697-78. Someone on Ebay was selling a bunch of these so I ordered one and it did NOT work despite PacParts claiming it would. He was kind enough to exchange it for another one which also did not work. The drive had the same form factor but there's a difference in the internal electronics. A lot of the functionality of the head unit seems to depend on the electronics in that drive so without it I lost most touch screen controls and it pretty much rendered the unit useless.
Luckily there's a solution. I was able to swap the PC board between the two drive units since the mechanical portion between them is identical, and the mechanics were all that was wrong with my original drive. 5 screws attach the bottom cover of the drive casing, and the PCB is easliy acccessible, held in place by 1 screw. You need to detach 2 ribbon cables which are held in place by flip down locking clips. The screws are very small and you need to pay close attention to how everything is seated so you can reassemble it the same way. It's a job for someone who is pretty technically inclined.
As for the head unit you need to pull the power plugs or you risk blowing a fuse even with the ignition off because the ribbon cables carry constant voltage. Remove the top cover and then remove the screws from the rear rail holding the drive down (but not the front rail). You need to remove the plastic brackets on the side that hold the screen tilt mechanism in place (and pay close attention to how the guides work so you understand how to replace them). Then you need to pull (hard) on the tilt screen rails to extend them out of the chassis so you can manually flip the screen down and access the screws holding the trim panel behind it. Remove the green clamp holding down the ribbon cable, it's held in place by 2 tiny screws. Disconnect the ribbon cable which is held in place on the back of the screen by a flip-down locking clip - hint, flip it up from the rear. Remove 6 screws holding the plastic trim behind the screen in place. Watch out for a small metal bracket behind that trim that may fall out of the chassis when you remove it. Then take out the remaining 2 screws holding the optical drive on the front of the chassis. Now you can flip the drive up and over to the right so you're looking at the bottom of it (see photos earlier in the thread) and detach the ribbon cable, again held in place by a locking clip. Now you can attach that ribbon cable to the new drive. Reassembly is pretty much the reverse.
Again this project requires a lot of disassembly, small parts, and a good understanding of how things fit together so it's not for the faint of heart. I didn't realize what I was getting into when I bought the updated "replacement" part on Ebay but I can now play discs again so maybe it was worth it. Good luck.