Tv is coming on for brief period and shutting down also constant flashing of green led light on front of tv

These blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit section inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power LED, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating procedure, to many popular brand TVs and other devices.
http://electronicshelponline.blogspot.com/
http://electro-medical.blogspot.com/
Blinking codes details of many popular brand TVs are given. Surf the site with patience.
If blinks continue without any pause, the main board is faulty.

These blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit section inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power LED, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating procedure, to many popular brand TVs and other devices. http://electronicshelponline.blogspot.com/
Blinking codes details of many popular brand TVs are given. Surf the site with patience. If blinks continue without any pause, the main board is faulty.

The red light is key to your issue---is it blinking in a sequence--constant blink or for example 3 blinks, pause and 3 blinks?

Does the led light flashes green continually?

Check if you can access the operational error code. The TV must be in shutdown and then press the front panel "activity" and "channel down" at the same time and hold them for 5 secs.

Led light will flash 2 digit code separated by a pause.

23 - 2 blinks pause 3 blinks

Let me know the result...

Is the projector receiving a source signal? if not it will power itself down after whatever time you have it set to do so when no signal is present.
Just an idea?

Unplugged my Sony for 36 hours from wall and it solved the problem

I will need your model number in order to help you as well as need to know if the led blinks a certain number of times or is it a constant blink.

There are 4 1000uf capacitors on the DM board that prevent your set from completeing the boot sequence. replace these with the Radio Shack eqivalents and your problem should be resolved. The 4 capacitors are located right next to each other in a group. Hope this helps.

Please study the procedure at the following address.....
www.chrisandnat.com/projects/blinkingtv/blink.htm .....

use 1000mf 25v or 35v 105 degree capacitors to replace
original four 1000mf 16v..............if new ones are a little
too high,just lay them over on board........

Look it over..........let me know......................T.

Refer to owners manual will tell you what blinking light means. But at the front not at the back.