I recently bought a used Denon DVD-2900 and was disappointed when I first powered it on and saw that the entire picture was green! I checked the component cable about three times just to make sure it was plugged in correctly, which it was. To get it working, all I did was switch out the cable! Funny...the cheap DVD players all worked fine with the old cable.

M60s
VP150
QS8s
Marantz SR6003
Samsung LN52B550
Oppo DV-980H
Insignia NS-WBRDVD