Samsung UN40D5500RF; Power On, Backlight On, but no picture

[8ternity]

Hi,

I had an Samsung 2011 model; UN40D5500RF get an problem.

The TV power on,
The Backlight Goes On,
Black Screen, no picture;
No clicking relay listeting, totally open but don't know if an relay is normally clicking when power on.

Power board seem's to work pretty well. Fuses OK.

Did someone know what is the problem? It's the second model i had which does exactly the same problem. My friend would ask for help so made research on it.

Thanks a lot !
8ternity

[Hamie]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

Check both sides of the tcon pico-fuse.

Do you get 12v either side?

Black probe chassis ground, red probe touch either side of fuse to confirm 12v is present.

[8ternity]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

Hi Can you highlight the part or give the # to must be sure.

Did it's the 125V 3A fuse?

I will check that tomorrow, i will need to unassembly again. I will let you know tomorrow the answer.

[Hamie]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

Yes the 125v 3a fuse on t-con.

[8ternity]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

Hi;

Pico Fuse show 12.80 volts input; and 520 Mv on exit.

I bypass the junction of the fuse, and im getting verticales multicolors lines all the screen. No sound, no menu.

[Hamie]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

Ok so you have 12v going into the fuse and only 0.5v going into the tcon.

You have an open fuse, sometimes you can get lucky and replacing the fuse will fix the board as they sometimes fail by themselves. Other times it's blown for a reason and there's a s/c on the tcon.

Do not just put a piece of wire over the fuse or you may damage the panel.

[8ternity]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

I use an alligator clip (to clip the fuse like a wire jonction) after that to double test if the screen are open.

It's smells fumed; the screen show vertical lines all over the pc.

[Hamie]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

You may have damaged your panel.

That's why I said don't jump the fuse.

[Hamie]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

Eitherway your tcon is faulty, replacing it might still fix the TV. Fingers crossed it didn't damage the panel.

[budm]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

Or the panel is bad (shorted TFT ICs drivers) that took out the fuse.

[tom66]

Re: Samsung UN40D5500RF; Power On, Backlight On, but no picture

Or the T-con has an onboard fault, like a shorted highside FET in a buck converter. Fuse blew, panel saved normally. When fuse is jumped, full PSU short circuit current went through it, and fried panel.

Just an example - NEVER JUMP A FUSE!
I can't believe how many people do this!