I would like to ask about who had encountered a problem in Bose acoustimass 10 series IV like the active subwoofer speaker unit, the bass sounds at first but after a few songs, the bass went off, the bass goes back again after I replugged it to the mains. I thought that the problem was from the Sony Receiver but it wasnt because I connected another amp and the bass was there. I replaced the heat pads of the transistors inside with mica and thermal grease (cause I thought it was an overheating issue) but the problem still persists. I've checked the 2 embedded subwoofers and their fine. The components of the main amplifier are almost smd, please can someone give me some advice cause Im confused 🙁