We have about 4 - 5 Telex KP-12 Panels that we use on a regular basis that have a display problems. The display for the local menu is supposed to have 8 dashes across it so you know the display is on and functioning. At random times half the display will go out (so only four dashes appear). Anyone that has used this panel knows that these dashes turn into lettering of menu options like "DISPLAY" or "SERVICE." However since half the display isn't lighting up I can't read these menus and access them. I know that the menu options are functional because I can still make changes to the panel locally; but I have no idea what I'm changing because I can't see the fully display, only half of words or sometimes none of the words. I was told this was a either an display driver problem, or a cheap environmentally safe solder that was used in these panels that and has been known to cause problems. I'm not wanting to send in 5 panels to the shop for a repair that I can do. If it is a cheap solder I can fix it easily, but if it is a driver problem I can't update it without sending it in to get a new driver card. Any thoughts?