This amplifier does work. There is output from the amp . I have been using this amp for years. I only listed as “for parts or not working” because the first positive speaker terminal screw has broken off inside( please refer to the last pictures) as a result that first positive speaker terminal cannot be used .. the other three speaker terminals work fine . I have been using the second positive speaker terminal and either of the two negative speaker terminals to hook up the subwoofer … please note that one of the mounting tabs has broken off and the plastic end cap on the same side as the missing mounting tabs o has a crack … I am being as descriptive as possible so you know what to expect please refer to the pictures for cosmetic condition as no refunds are offered … I can send you video of the amp hooked up to a sub it works fine just the first positive speaker terminal screw has broke off inside