The advertised ratings of the transformers are usually quite different than the actual measured ratings. Like stereo amps in the seventies. Yeah it can do 200 watts but only for three seconds before it blows.
If you tested the transformers with a common test, i.e. resistor load, volt/current meters and a true wattage meter you would know what the actual wattage are. You migjt be very surprised by the results. Unregulated power supplies will sag under a load. Wall warts are notorious for that.
