Samsung UN40ES6100 no backlight

[budm]

Re: Samsung UN40ES6100 no backlight

http://www.electronica-usa.com/product_BN96-21460A.html

[dsc]

Re: Samsung UN40ES6100 no backlight

As always thank you Bud, a quick question though.
I was attempting to source a scavenged part locally. One of the very few repair guys remaining on the cape questioned the fact that the right string of lights was fine and didn't flash when I powered up the set, nor did it illuminate when I had the main board disconnected. He said that I should be looking for other problems still as he has seen some sets with just half the pic illuminated. Any thoughts?
As a side note, he has been doing a large amount of warranty work on LG's as they are experiencing backlight trouble and even has successfully replaced a set where the customer threw the remote at the tv and cracked the screen because of the premature failure.

[dsc]

Re: Samsung UN40ES6100 no backlight

So for further advancement, I now get a quick flash of the led's when I plug in the PS, main disconnected.
Any advice where to look now?

[budm]

Re: Samsung UN40ES6100 no backlight

So for further advancement, I now get a quick flash of the led's when I plug in the PS, main disconnected.
Any advice where to look now?

So now all the LED strings do flash on for second?
On post 19 you indicated 'I found that the left string of led's was fine but the right side had no less than 10 not functioning at all.'
What did you do?

[dsc]

Re: Samsung UN40ES6100 no backlight

I removed the bad string, right side less tested ok individually. Located a known working left string that I borrowed for testing. I installed the PS only and plugged it in. All leds flashed once. Tried again and a few less flashed, third time only a few on each side flashed. Allowed it to sit for a while and tried again with the same results.
In all I have replaced the IC, two surface caps.
When I first got the set the leds did not flash at all. They only flashed after surface caps were replaced.

[budm]

Re: Samsung UN40ES6100 no backlight

So the bottom line is that each LED on all the strips tested OK, right?

[dsc]

Re: Samsung UN40ES6100 no backlight

Yes, all of the ones on my original right side tested good, though a couple were slightly dimmer.
The left side I borrowed were all good and even in illumination. I had to return the left one so I am now back to just one good side, which by the way does the same single flash.

[dsc]

Re: Samsung UN40ES6100 no backlight

Sorry for the confusion, in post 19 I incorrectly listed the strings. When I pulled them I noticed what I had done (my having thought as a mechanic) and then started to reference them correctly.

[budm]

Re: Samsung UN40ES6100 no backlight

Can you leave the meter probes on the two legs of the cap C9110, then plug the TV into the outlet and turn it on and observe what you see on the meter (meter should be set to 200Vdc scale or higher)?

[dsc]

Re: Samsung UN40ES6100 no backlight

I'll do that tonight, I haven't looked at the cap, do I need to be concerned about polarity?

[budm]

Re: Samsung UN40ES6100 no backlight

Black on negative leg, red on positive leg.

[dsc]

Re: Samsung UN40ES6100 no backlight

Ah, just looked at the photo of the board and see the cap you are instructing me on, easy enough.
Sorry for the daft question, I was picturing a board mount cap for some reason.
Will post the results later.
Thank you again for your guidance.

[dsc]

Re: Samsung UN40ES6100 no backlight

I came up with 260, it was bouncing around a bit, 257 to 263 then settled to the 260.3 range

[budm]

Re: Samsung UN40ES6100 no backlight

If you look at the chart on the power supply board, the LED Voltage is printed as 191V 367mA, so to me the load (LED strings) is no good and allow the Voltage to go up very high.

[dsc]

Re: Samsung UN40ES6100 no backlight

I get the same voltage with the LED disconnected too, from what I have read that should be correct?

[budm]

Re: Samsung UN40ES6100 no backlight

No load Voltage (LEDs string not connected) will be higher then when the Load is connected. Some circuit will go into protection mode when it detect higher Voltage than it should be. In your case, 260VDC is not normal.

[dsc]

Re: Samsung UN40ES6100 no backlight

Seems as if everyone, including Electronica, is sold out on the LED strips.
Trying to source out the LED's themselves is proving to be frustrating too.

[flocko]

Re: Samsung UN40ES6100 no backlight

I think I have the LED edge boards that you need But I am in the UK? they come from a UE40ES6300 and show part numbers R20491 40DBTF+ L20217 40DBTF. do they sound like the right ones?. I dont think you will find replacement LEDs as they are side mounted and these are the first of this kind I have come across , unlike the LEDs fitted to LG/Sony edge lights you find in most sets

[dsc]

Re: Samsung UN40ES6100 no backlight

@ flocko
The part numbers that comes up for my set is BN96-21460A and BN96-21461A.
I looked up the numbers you listed, they look similar but the connection wiring is different.
I have two blue and one white on one side and two black and one white on the other.
These LEDs are interesting, side tang surface mounted.

[flocko]

Re: Samsung UN40ES6100 no backlight

Yes see they look the same ( did you see my listing on ebay UK) but have now seen you have a BN44-00502A supply, the set that these come out of has a BN44-00518A so LED output connector not the same, I have not seen any other set that has these side mounted LEDs, the norm is back mount. Good luck the search goes on Flocko