Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

[JeffJ]

As the title suggests, Hoping its not bad LED(s) if so, this is the second tv that I've had, purchased new that has failed LEDS just out side of warranty.

This LED failure is getting silly.

As you can see in the pictures a darker horizontal line in the middle of the tv and the bottom edge of the tv is ls also darker.

[dick_barton]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

It does look as though a led strip is not working.

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

So i had a chance to get back to this unit. I haven't tested each strip individually, however i think i figured out what caused 2 of the strips in series to go dim. Has any one ever seen this happen before on a Samsung led strip?

The Blown part on the 24V pad is marked 4EJF, comparing to other strips. not sure what it is though.

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

I've successfully tested the leds and all are well except one on this strip i pictured above with the damaged component. any one have any idea what it is and what i can replace it with? I've already replaced the LED with a doner led. it is tested and working

[vinceroger69]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

maybe a fuse? maybe budm has a idea what the part maybe and a replacement

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

This is the first strip I've had with these on it.

After its fixed, I'll have to explain yet again, not ot turn the Back-lights up to infinity lol.

[rickou]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

is fully working now?

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

is fully working now?

Not yet I still have to replace that blown component on the 24V rail. I have a feeling it's a diode but I am not sure what the specs would be i can't find information on it. Waiting for the TV repair gods on here to possibly advise.

[vinceroger69]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

does the part on the 12v rail read like a diode when tested?

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

does the part on the 12v rail read like a diode when tested?

Yes it appears so, so do the others on the non blown strips.

Each strip set has 16 LEds in them, the strip with the bad component and led had seven and its sister in the set has 9.

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

Ok, so tested all 144 leds all working now with a meter set to diode mode. All light.

Just need to figure out this blown part on the 24V pads and this baby is back in business!

Hope one of the Repair gurus drops in

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

Here is a picture of the parts on another strip, In case some one can help me out.

[Khron]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

Could it be a 3v zener from this range?
https://cdn.badcaps-static.com/pdfs/...6b90bb8012.pdf

More to the point, would it make any sense for that to be a 3v zener there? Can you figure out what it's connected to, and how?

[flocko]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

Looking at the SMD component code book the marking 4E is a Vener Diode, Vishay MMSZ5234 or Semtech MM1Z3V0 other make are also available. All show same data and marking

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

Here is what my meter tells me.

Red is from the Positive feed on the led connector. Blue seems to run along a trace to a pad. which ends up being the negative contact for my meter to illuminate/test the last led on the string. The blue looks to be the Return/ground on the circuit.

So does this make sense that it would be the zener as suggested? Looks like the other part according to the code is a MM3Z18V?

[Khron]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

... And what did i say?

Just too bad these markings are nowhere near "universal" or unique, between various components, though...

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

Alright so that one is definitely a zener then. The other one should probably be replaced too. trying to figure out what that is for sure.

Or do you think i could remove them and run with out it?

Or maybe a suitable work around suggestion?

[dick_barton]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

Can you run up a working led strip and measure the voltage across it ie. 4E component.

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

Can you run up a working led strip and measure the voltage across it ie. 4E component.

Good idea, 9 LEDs in a strip so 48 volts should do it.

Probably a safer idea to just force BL on and measure though. So i'll do that

[JeffJ]

Re: Samsung UN50F5500 LED LCD TV - Bad LEDs or something else?

It measures 4 volts across the part marked with 4E and i didnt get anything across the part beside it which is odd, maybe ill touch up the solder joints ot be sure my probes are making good contact.