Hello needs Help for Harman Kardon AVR 5000 🙏

[suresh105]

Harman Kardon AVR 5000 model 5.1, hardly used, slowly loosing sound on each channel, first centre, R/channel, L/channel front and rear, and subwoofer finally, no sound from any 5.1 channels!
When switches on AVR, Relay click, all front panel features illuminates, FM properly turnable, all front panel switches work. Features can be selected,
But no sound. Could you please suggest known engineer to sort no sound problem in AVR 5000 H/K
I am from trivandrum, Kerala, India