From your signature I see you are in Mumbai. Please check the mains voltage. I have raised complaints with MSEB on high voltage being supplied to our society in Pune. The normal voltage used to be 230v +- 5%. Now it is 240 +- 10%. Many people in my society have been losing the TV sets, microwave ovens, led bulbs, tube lights, laptop adaptors since the lockdown last year. I too lost one computer SMPS to these high voltages. Most equipment made outside, the max voltage is supposed to be 240v. In the nights, the voltage goes to 250v. Most probably your subwoofer standby SMPS has gone bad. Most avrs, amps, subwoofer now days have a small standby SMPS to power on circuitry that can switch on the main transformer when you press the on button on the unit or on the remote.
My Yamaha AVR standby SMPS blew last month. It would switch off because of protection circuitry. The link to the problem is here
. Luckily I know a bit about electronics and I was able to repair it myself by replacing a SMPS ic.
Now I have all important equipments on voltage stabilizers. I have also connected voltmeters in almost all rooms. Every equipment that has failed since last few years I have found the fault always to be in the high voltage section of the SMPS. These SMPS have been blowing out like crazy since last year. Transfomer based PS are more robust, but less efficient. Due to regulations most avr, amps, subwoofers, etc have a standby SMPS instead of transformers to draw very little power when in standby state.
While searching for searching for India's voltage regulation standards I find that the normal voltage now in India has been quietly changed to 240v +- 10% in 2014. Which means the voltage can be as high as 264 volts and you can't complain. The reason stated is "economic reason" Here is the link https://www.myelectrical2015.com/2019/04/standard-alternating-voltage-and.html
. Why such high tolerance for power generating equipments beats me. My guess this is to do with saving money for the private players who have enterered electriicity generation business and now they can install sub-standard equipments at lesser cost.
I would urge FM to check the voltages in their respective states. I'm not sure if this high voltage thing is only in Maharashtra or throughout the country.
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