Hmm
Maybe you should write a little sketch that counts up from 0 to 255.
In the first line you would do a lcd.write, and on the second line a lcd.print of the value you just printed.
Delay a second or so, so you can make a note of the chartacter you're interested in, and then next value.
Or to keep full track, wire up an up and a down button and scroll the characters.
If you happen to have an lcd keypad shield, this should be quite easy.