My SAMSUNG UA40D5030 LED TV is not powering up

[gauravped]

Hi All,

I have SAMSUNG model number UA40D5030PR LED TV which I bought in 2011, working fine till September 2017. 
All of a sudden while watching TV, it turned off on its own. No Status LED, no backlight, and thus no picture. I tried to turn it on with Remote and both with front panel power button. It is completely dead.

Upon opening the backpanel of the TV, on the power circuit board, I noticed that the Fuse, marked as FP801S (250V,5 Amps,Ceramic Through Hole type) was blown. Thus, I went to hardware shop, and bought new same specification fuse and replaced it. Within 1 second of powering up the TV again, the new fuse also blew. I realized that blowing fuse is not the real cause. Something else is drawing higher current which is making fuse blow. So I surfed the internet, did some reading, and using just a multimeter to troubleshoot, I came to know that Power MOSFET marked QP801S (MDF11N60 from Magna Chips) has all Gate-Drain-Source Terminals shorted. Also, one Capacitor marked CP802S (PILKOR WK113) is shorted. I can't confirm them as failed components, as I could not get the exact circuit diagram of the power board. All circuit diagrams I got online are of Power Board part number: BN44-00473A or BN44-00422A while my TV uses power board part numbered BN44-00473B.

Can anyone provide me circuit diagram of BN44-00473B?

Also additional inputs for troubleshooting the board from experts are highly appreciated. This is the first time I am troubleshooting my home appliance.

[orbanp]

The "A" and "B" version boards look pretty much alike (from eBay pictures), so I think you should be fine if you have the schematics for the "A" version. There is probably only some minor difference between the versions.

As for the repair, do replace the shorted components, and also do check the ESR of all the electrolytic capacitors and do replace the questionable ones.

EDIT:
You could also test the PS out of the TV.
For safety do  use an isolation transformer!
Depending on the controller IC used in the PS, the PS might require some load to work! So put some external load on it, like light bulb, or power resistor.

A quick search did not turn up for me the schematics of the "A" version board.
If you post the schematics you will probably have more help!

Good luck, Peter