My Sony Bravia 52W4100 comes on for about 10 seconds, then on its own switches to the stand by mode. The picture and sound go off and the standby light flashes. It stays this way until I unplug it then the same problem repeats. No buttons on the TV or the remote have any effect. The TV is about 7 months old.

SOURCE: Flashing Standby Light (6 times every 2 second interval)

A 6 flash error indicates a problem with the backlight. Your set is less than a year old and still in warranty, so you should contact Sony and arrange for a service call to get it repaired.

SOURCE: tv tunrns on then goes to stand by flashes 4 times & repeats

turn tv on picture comes up 2to3 seconds later tv blacks out then stand by red light flashes 4 times in a row repeatedly..can not turn on or off when stand by light starts flashing but before tv blacks out you can turn tv on and off repeatedly and picture and sound work.You have to unplug power cord for 30 seconds after stand by light comes on to get tv to turn on.

SOURCE: Sony Bravia LCD TV stand by red light flashes 13times

Really? Nobody has a better solution? I have the same problem and the tv's about a year old. That's it!
Crazy!

SOURCE: my sony bravia tv is flashing red stand by light

Try leaving the TV unpugged for 30 minutes so the TV can reset itself.
If that doesn't work, most likely the TV has a power supply related problem. The most common thing to go out is the circuit board that supply power to the screen. Commonly called a Backlight Inverter Board.
I can't say it's 100% the problem because I can't actually look at the tv over the internet.
If by chance the TV is still under warranty, go that route.
If not under warranty and If you have some electronic experience, you can purchase a Service Manual over the internet and diagnose the source of the problem and fix it by soldering in the new part. The Service Manual will give you flashing red light codes, circuit diagrams, test points, and part# lists. Usually, cost under $20.

I hope I shed some light on the subject for you.

SOURCE: Sony Bravia standby light flashing 6 times

there is a bad ground may on the cable check the voltage on the cable & set if on cable call the cable company. if tv call sony they may help with cost may be still under warranty