I have a Panasonic SA-AK333 stereo. When powered on with it's speakers attached, it shows an f61 error and turns off. If I plug in the speakers, it turns on fine and all the buttons and the screen act like its working fine but there is no sound. I opened it up and it doesn't appear that anything is going on inside. There is absolutely no noise and the fan is not moving. Alot of googling has got me nowhere so if anyone knows what is wrong and if it is fixable, let me know. thank you.