RGB monitor technical questions

[aclark@deathtospam.envirolink.org]

I have been trying to use a Magnavox RGB Display 80 on both an Apple //e
(with AppleColor RGB card) and an Apple ///.  I have been unable to get
the monitor to work with either machine.  On the //e, normal text
displays as yellow text on a red background.  The card is set for black
background and white text.  Graphics don't work at all.  Just gibbersih
yellow lines on the screen.  The monitor doesn't work at all on the
///.  (In composite video mode, this monitor works beautifully on the
//e and ///.)

I noticed something on the back of this monitor that makes me suspect
that it might be incapable of handling RGB output from the //e or ///. 
It says that the RGB input to the monitor is for TTL (Transistor to
Transistor Logic) RGB signal.  But my Apple /// Owner's Guide mentions
that the Color Video output port in the back outputs seven signal types
simultaneously, only one of which is TTL RGB signal.  I get the
impression from reading this stuff (I'm not enough of a techie to really
understand it completely) that you have to have some hardware between
the /// color video output and the monitor to sort out what signal to
send to the monitor and what to ignore.  Does anyone know if this is
true?  

On the //e side, I know very little.  I'm not sure what type of RGB
signal the AppleColor RGB card produces.  All of this is complicated by
the fact that I know that this card can be flaky.  There's no guarantee
that it is working right and producing the right signal.  Help?!? 
Anyone?!?

Thanks!

Art Clark