# Sony home stereo randomly power cycles



## buddyochoa (Jul 20, 2009)

my sony stereo will randomly turn on and after a while turn back off. I dont know whats causing it. Is there anything that would interfere with it?


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## octaneman (May 13, 2009)

Hi buddyochoa


Does your stereo have a timer ? If you are comfortable opening your stereo and do a little probing with a test meter then here's are some things to check. Some stereo's have a safety shutdown feature that prevents it from overheating to prevent components from being burned. The circuit is located on the power supply, it has a flame proof 2.2 ohm resistor. The resistor will get hot causing it to open, the power supply will then shut down cool off, and re-start again. Another thing to check are the capacitors, they are barrel like components that become bloated and misshapen when they are burned.


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## ebackhus (Apr 21, 2005)

I like Octane's idea on the issue. The thermal trip protection is a very likely culprit based on what you're describing. My HT head unit gets VERY hot at times but I keep it isolated on a top shelf of a stand where it can be cooled easily. If it's surrounded by other components then the heat given off by them will also be a contributing factor.

I recall doing some cable work for someone and opened the cabinet where they kept their components. HOT LIKE HELL. No wonder they kept having problems...


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## buddyochoa (Jul 20, 2009)

It ramdomly will turn on when its shut off. There no heat around it when its off


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## octaneman (May 13, 2009)

The power supply still has to be checked to determine what type circuit is being used, either an opto-coupler or an oscillator switching type p/s.


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