Kenwood kvt 911 dvd head unit

Question

Hello i just brought a kenwood kvt 911 from auction. Sellers said it was working when taken out. I haven't install the unit in my car yet because its to dark outside. But i have try to see if the unit powers on and functions. I put red & yellow to positive and black to negative. the unit powers up but monitors doesn't slides out and unit turns off in about 3 seconds after i tap the positive and negative. When i press the open buttons it powers up then shuts down again. Do you know whats going on? and whenever i do tap it to power it up , it makes a sound like a cd is ejecting from the unit.