look on google for the Nokia monitor test pattern - it allows you to display separate R, G and B screens (using a PC to feed) - look for any dead pixels on each of these panels. I think that stuck pixels are visible on White or Black screens. The Nokia program also has patterns to test for convergence (which is also important imo). If you can't feed from a PC, you might require something like Avia.
Note: just remembered that the 300 has R,G,B screens in the setup menu that you can also use (hold for a few seconds on the [OSD] menu option). It even has convergence patterns too.