I need a large font issue of my channel line-u

Sorry...you cannot change the font size on the on screen guide.

I don't think you are going to find any channel lineup list with such a large default font.  It makes the display much too large and spread out given the number of channels.  If you really need to see the display in such a large font you can zoom your monitor, or zoom the browser page display (most browsers can to that), or "print" to output to pdf and enlarge the pdf display with whatever pdf viewer you use (Acrobat can do it).

Note, FWIW, and in case you don't know, when you display the Guide, you can use your enter/zoom button on your uverse S10 remote (or Options button on your S20/S30 remote) to bring up the "Guide Options".  In the "Guide Options" press U-verse Packages->U200 to display the Guide with only the channels included in your U200 package.

Can you generate a smaller font one on your computer?  If you can, then here's what you do:

1.  Select and copy it (try using Ctrl-A to select all of the text at once, then Ctrl-C to copy)

2.  Paste it into a word processing app that lets you set the font size - for example, WordPad

3.  Select the text, and change the font size to 16