My Mitsubishi WD 60738 DLP TV is attached to a cable box DVR system. Part of the settings on the remote control let's you select 480, 720, or 1080 format...Mine somehow had them ALL selected and as I change channels it would have decipher each one before selecting the appropriate one therefore taking at least 10 seconds which is s bit frustrating. I had the cable tech out and he showed me how to manage that feature. Go to SETTINGS on cable remote and hit MORE SETTINGS. Scroll til you find Video Output Formats and select only 1080i. That will allow you to go to each channel with minimum time loss. If more than 1080i is selected then de-select all except that one. Your cable company may be different from mine so the way to use your remote may be different....
I'm not sure how mine got changed but it sure has been frustrating the last couple of weeks.