i don't know if you have tried yet, but your odd resolution (496x384) may not be compatible... usually the list of compatible resolutions for big screens and projectors starts at 640x480.... even then sometimes you cant get it to pick up the signal.
had a 42" lcd used with a PGA golf computer running 800x600 at 60hz. plug in the vga cable, screen says can't sync to signal.... even though the compatible resolutions show 800x600 60hz as compatible, it obviously wasn't. i ended up using a DVI to VGA adaptor and using the DVI out on the video card instead of the VGA. and it works... at 800x600 60hz. WTF?!

*throws hands up in the air and stomps off*