Slow to turn on Phillips flat screen tube big screen

That is a common issue with the last generation of the phillips big screens, the best answer for this is one that i got at a meeting with phillips service several years ago. On philips the tv will not show a picture till the tubes are balanced out, simular to sony, but in a phillips if the white balance is not correct the picture and sound will be muted till all three tubes have warmed up enough to produce a good white balance. As the set ages the tubes become weaker and this procesess takes longer.