Mits WS55513 DVD Issues

I have an older Mitsubishi RPT WS55513 that has the older DVI input. On my TWC Scientific Atlanta HDDVR I have it hooked up TV DVI to DVR HDMI an adapter cable works great. I also just bought an up converting Sony DVD player to hold me over till I get the Vizio BRP I hooked up the Sony DVD to my other TV the Vizio DLP and It up converts and works great. I tried to hook it up to the Mitsubishi RPTV using the HDMI connections and it doesn't work I get colored wazy lines no picture! Now this last year with a Samsung Up convert DVD I called Samsung and they said TV and the Samsung DVD Up convert aren't able to "shake hands" due to the TV being older? So I returned it and hooked up my old DVD progressive dinosaur, LOL!! I hooked back the Cable Box:mad: DVR via the same cable DVD HDMI and it worked flawlessly upgrading the signal to 1080i what gives??