I have just had a 3d80 arrive from Ebay and it has a strange fault. The 3D button appears to work and lights up the light on the front, however it doesn't seem to activate the bass amplifier unless i hold the button down. if i let the button go it will work for about 40 seconds and then the bass disappears again and the light stays on. There is no crackling or anything. could this be a faulty amp or switch?
