Question about turning off Dragon

[Dimitar Georgiev]

I have an issue with my Dragon at home. I am not sure if this is potentially serious thing or it is harmless. When I turn off the power I hear realtively loud 'boum' in the headphones. The strength of the 'boum' does not depend on the volume position hence it should be caused by voltage induced by the power-off of the deck. There is a spark-killer inside this model and it consists of resistor and capacitor in series . The spark killer itself is connected in parallel to the primary coil of the mains transformer so upon turn-off it will short-circuit the induced high voltage spike so it won't allow it to go to the secondary coil. Is it possible that the problem is due to bad cap or burned-out resistor in the spark killer ? Somebody had or fixed similar issue ?

Thanks,
Dimitar