I'm trying to connect my cable box or my DVD player to a mitsubishi 1080 and I'm only getting a blue screen on every source outlet what am I doing wrong?

SOURCE: Mitsubishi VS-60805 Rear Projection won't operate in HD mode with Cable Box

Since this is an older first generation (1999) HD TV it may not be compatible with newer HDTV receivers because the standards back then were different - Make sure the HD cable box is plugged into the HD component inputs on the back of the TV (not the DVD inputs) and that the menu setting on the TV is set to DTV (not RGB) video. This TV will only accept 480i and 480p signals on the DVD input. Also the HDTV input will only accept 480i,480p and 1080i (it will not work with a 720p signal,make sure your cable box is not set to that mode)

SOURCE: No High-Def via monolink(HDMI) connection

Troubleshoot first by self diagnosis

SOURCE: how do i get 1080p

How did you get 720p? I have having trouble viewing anything above 480p. When using my directv HD DVR, the screen goes black when it tries to show anything above 480p. Is it the tv or the DVR?

SOURCE: mitsubishi 55 in. 1080 series

If I remember correctly, this TV has a couple of constraints that will cramp your style:

1. It supports 480i, 480p and 1080i. NO 720P
2. It has component video inputs, but NO HDMI. (as you stated)

There is no easy solution here, because I've never found an upconverting DVD player that would upconvert anything past 480p using the analog component outputs...

So..

Perhaps you can find an Upconverting BLU-RAY disk player that may allow older DVDs to be upconverted to 1080i via the component outputs.

MOST Blu-Ray players allow 1080i output via the analog connections on Blu-Ray discs, so perhaps there is your solution.

SOURCE: big grey box keeps popping up on screen...especially with dvd in

Make sure the SAP (second audio portion ) is not activated