Fender Rumble 25 amp not working

It keeps making this blaring white noise sound, like an extremely lound air conditioner, whenever turned on. none of the knobs affect the noise and if i plug in my bass its like it isnt plugged at all nothing registers. I hadnt used it in a while but it was stored in a safe place so it couldnt have been damaged in that time. Anyone know the solution to this issue?