Harman Kardon TS-7 Subwoofer - Wont come out of standby - Assistance to troubleshoot (have schematics) : r/AskElectronics
Harman Kardon TS-7 Subwoofer - Wont come out of standby - Assistance to troubleshoot (have schematics) : r/AskElectronics
Harman Kardon AVR 8000 Issue When Powering On | AVS Forum
Basically, all Harman Kardon amplifiers (including subwoofers) show power supply issues after a few years « The Wiert Corner – irregular stream of stuff