The subwoofer shows no standby light and refuses to power on at all. This points to a blown primary fuse, shorted rectifier diodes, or a failure on the standby line.
Protections & Reliability
If the main 48V rail is failed, but the ±7V rail still functions, it is likely the primary switching circuit, rather than the secondary side, that has failed. Replacement Considerations hys3c210-cs power supply
Most repairs involve replacing dried-out electrolytic capacitors or blown Schottky diodes. 2. Complete Unit Replacement The subwoofer shows no standby light and refuses