when testing different circuits that have various lighting or display panels that use edgelighting causes the power supply to get loaded down because when the type of lights or lamps resistance has increased from heat or aging i'm guessing. What lights or lamps increase it's resistance from aging or years of use. The older lamps get the tungsten wire increase its resistance. I disconnected the lights or lamps from the power supply and it pulled up the power supply. The lights or lamps resistance has increase through years of use or aging, any reasons why?