HI;
With me it was the trimpots (trim potentiometer), which you can google how to open up the power supply and do the simple adjustment with a philips screwdriver. It's simple, a 10 minute job. Don't worry about voiding the warranty--It's utterly worthless. To repair a PS3 worth $300 is $150 plus shipping I believe, half the cost of buying a brand new one. Since I did the adjustments I have not a single crash or random power-off. The updates fail every time, but that's Sony's incompetent or lazy software and firmware development team who don't understand the product, not a failure of the overworked Chinese worker or mis-calibrated machine that incorrectly adjusted the trimpots.