Has anyone found a source to replace the Vacuum Fluorescent Display used in our C5's that dim after a year or two. One one think that GM would have fixed this but I hear that all GM vehicles that use the display experience dimming after time. Mine is starting to go.


The vacuum fluorescent display (VFD) is constructed of a hot cathode of tungsten filaments, a grid, and a phosphorescent screen that is the anode. The components are sealed in a flat glass envelope that has been evacuated of oxygen and filled with argon or neon gas.
A constant voltage is applied to the hot cathode, which results in tungsten electrons being released from the filament wires. The grid is at a higher positive voltage than the cathode. The freed tungsten electrons are accelerated by the positive grid wires and pass through the grid to the anode. The grid ensures that the tungsten electrons will strike the anode uniformly.
The anode is at a higher positive voltage than the grid. The phosphorescent coated anode (screen) will be luminescent when the tungsten electrons strike it. The display is controlled by which segments of the screen are activated by a digital circuit. If the segment is activated, the screen will illuminate. If the segment is not activated, the electrons striking the screen have no effect on the phosphors and the screen remains off.
The segments of a VFD can be arranged in several different patterns. The most common are seven- or fourteen-segment patterns. The computer selects the sets of segments that are to emit light for the message.
The VFD display is very bright. Most manufacturers will dim the intensity of the VFD to 75% brightness whenever the headlights are turned on. To provide sufficient brightness in the daylight, with the headlights on, the headlight switch rheostat may have an additional detent to allow bright illumination of the VFD.

The poll is just to see just how many of us experience the dimming problem. A yes/no answer is sufficient.