anyone know what causes black banding?

[JarettS]

i have a (piece of crap) Magnavox NB500MG9 going HDMI through a pretty high quality HDMI switcher box to a (pretty old) Toshiba HDMI 27" CRT HD 1080p TV. i get these random weird shadowy looking black bands, usually horizontal bands across the screen and usually occur during low light scenes or light to dark scenes. i read some stuff on black banding and didnt get too much help in my travels through google and blu-ray forums. some people say that it is an incompatibility with the equipment and usually cannot be corrected. others say its outdated firmware.

i know i have crap equipment and i know im reaching here uh, but wondering if anyone here can maybe give me some advice or help me put the finger on it before i throw the Crapnavox out the f**king window!!!