How to Adjust Uverse Aspect Ratio (HD settings)
- 1
link,hd, are lit in this case
When you are subscribed to Uverse's High-definition service, the HD channels start at 1000, and goes from there. If your picture doesn't seem right, like the picture is not filling up the screen, either at the top, sides. or bottom, check in front of your AT&T's set top box, or DVR, and be sure your little blue HD light is on. You will see three lights on the front of your box. Unless you are recording, and if you have HD on, the link light, it is a green light, letting you know the box is working, and a blue light, when you are on a Hi-Def channel, this should also be illuminated. The red light is a recording notify. - 2
If you are on a High-Def channel, and you see the little blue light is not lit, you will have to adjust the Aspect Ratio. It is very easy, if you do these steps. - 3
from Uconnect
Make sure everything is turned on. Grab your Uverse remote and go to the menu. Navigate your arrows down to options, then maneuver the arrows to System settings, or system options, and select aspect ratio. Every time you select a setting, press ok in the middle of the arrows. - 4
navigation arrows
When you select Aspect ratio, move the bullet that is probably on 4:3, or wide screen, just select 1080 or 780, select continue, and then select start test. Once the selection stays in one of the Hi-def settings, select KEEP SETTINGS, and the exit to TV on your remote. Now if your selection fails, and goes back to SD or widescreen, you will have to START TEST again. If it will not stay in 1080, just select 780. Once the selection stays, check your blue HD light on the AT&T box to see if did come on.
Source...