This home audio system started making noise even when no input signal present, as long as it is switched on. It is not about ground issue or isolating the noise. It is coming from its amplifier circuit. Also its LED is not working and user interface went off while trying to find the problem. It uses TDA2030A and TDA2050 amplifiers with integrated bluetooth and sound modules. Kindly help
High frequency hissing noise which does not respond to volume up or down. Even when the system is off but still plugged on, continues to emit the noise