I once tried this and worked, but only once. So what you do is tap the power button until you see the red, then you tap the Ps3 top sort-of hard then press the power button again the second you tap the Ps3 it should turn on for an hour or so.Good luck with this, hope it works with you
Another one is trying to shake the Ps3 for 15 seconds or so, but I strongly recommend the other one this recommendation dosen't work that well, but let's just say it works good enough.