Original Xbox graphics chip problem....poor video please help!!!

I've got an un-modded, original Xbox that I just purchased used. When I turn it on, everything works fine but the graphics are distorted. It basically looks like when Windows is in safe mode on a PC or when the colors are turned down to 16 bit on a PC. I've tried this Xbox with three different newer TV's and I've tried many different games....does the same thing in every case. I don't see any way to adjust the graphics properties and I'm assuming the nVidia chip on the motherboard went bad.
Anyone have any ideas???
Thanks in advance!

 

Have you tried another video cable?

 

I'll see if I can find another cable and give it a shot. I wish there was a way to do a "master reset" on the Xbox. It really seems like someone changed the graphics settings on this one....however I guess that's not possible? Thanks for the prompt reply.

 

Let me know how you get on an hopefully I can help you further...

 

OK....I tried another A/V cable from a properly working Xbox and got the exact same result - poor graphics. Is there any possible way that the previous owner of my Xbox had some special HDTV A/V cable that allowed access to more graphics settings than I can access with my standard A/V Xbox cable? Just a guess...

 

There is HD settings, but they should revert to standard when the cables are changed!

You could try the method in my tutorials about 'My Xbox has no video, but sound'...

Also check the motherboard for any type of corrosion!