Monitor Problem

Can anyone answer this question?  I installed a BOSS all in one head unit  and added a 6" flip down unit then installed a 4.5" monitor in the passenger visor.  The problem that I'm having is that the visor monitor turns on but when the video plays all you see are lines moving up and down and the video showing is in black and white.  If I connect the monitor's video feed to another dvd player connected in another vehicle the monitor plays perfect.  There are only two wires coming out of the monitor a power and ground these are connected correctly. If I y-split the video feed coming out of the Audiovox unit both monitors play fine.  If I y-split the video feed from the BOSS unit the flip down plays fine and the visor monitor does not.  If I connect the video feed directly to the visor monitor from the Boss unit it still shows the lines.  I can not figure out why the monitor will not play with the BOSS unit but will play with the Audiovox unit. Now the question is.......... What is the chance that the Boss unit and the visor monitor are not compatible?  Unfortnately I do not know what brand the monitors are the guy bought them used.    ThanksT-Man

First try to unplug the flip down and then see if you have video on the visor....If so then you will need a video amplifier...cost about $20.00 and will solve your problem..