10" LCD Headrest Monitor w/ Shroud

I bought three of these monitors for their sleek design and ability to wall-mount. Even though they are designed for automotive use, I'm using them as monitors in a residential security system to view the camera images. They are connected to the DVR of my system and powered by a central 12 V source, but each of them has occasional problems. I returned one of them for a replacement early on in thinking it was only that one, but time has shown they all have glitches. My problems include: the monitor turning itself off regardless of how long it's been on, although it seems to happen most frequently after it's been first turned on; the monitor not responding to the face control buttons and then only the remote would turn it on or off; the volume display comes on and rises to maximum (I'm not using for sound) and will not disappear from the screen. If you lower it then it rises right back up, almost as if someone had their finger on the button. These problems all vary as to when they might appear or disappear, with no pattern. It cannot be explained away as a non-automotive use as my video source and power have been tested as fine. An e-mail to the manufacturer has gone unanswered so a phone call will be next. It's really a shame they don't work well as the size is perfect (like an iPad) and a spent quite some time deciding on these. Replacing them with something else I'll be satisfied with in terms of size and style is going to prove difficult.