Problems running xbox to monitor through switch

[wilko49]

So I just bought a DVI-D switch to run my PC and xbox into my monitor - I cracked it open, and it is just a big multi-pole 2-way physical switch.

Currently, I just swap the dvi cable from my computer for the hdmi cable with hdmi->dvi converter when I want to use the xbox, which works fine. Unfortunately, although the switch works fine with my monitor output, it doesn't work with the xbox's output. I know it works with the same cables run from a PS3, and I know that without the switch the xbox displays fine, so I'm a little lost as to why this won't work. Any ideas?

 

[wilko49]

I would have thought the problem there was probably with incompatibility between analogue and digital signals (not all switches will work with both), but I am using both purely digital signals, so I am sure that is not the problem.