my old Yamaha subwoofer, was a beast when it used to work properly, there are some marks, but have tried my best to clean, the sub powers on but no audio output, it's currently wired for passive connections, so the sub will need to be opened up to go back to active if fixed, but the subwoofer speaker is in fully working condition so could be used DIY as it is a great driver, drop me any messages happy to answer.
eBay