Samsung UN40ES6100 no backlight

[dsc]

Re: Samsung UN40ES6100 no backlight

Electronica has the strips back in stock so I ordered the pair.

[Oreyca]

Re: Samsung UN40ES6100 no backlight

I have a UN40ES6100 also with no backlighting. Sound works and a picture can be seen with a flashlight test. PWM_DIM = 0.85V DC. BLU ON_OFF = 4.89V DC. At the LED connector CNL802, with the connector connected, during TV start up: Pin 2 (R+) and Pin 3 (R+) they initially stabilize at 105V DC then go to 250V DC. Pin 5 (R-) and Pin 7 (L+) is 40V DC then goes to 190V. Pin 9 (L-) and Pin 10 (L-) are 2V DC then go to 80V DC. Any suggestion or help would be much appriciated. Even though it would probably be fun and all I would prefer not to disassemble the TV down to the LED strips just to blindly check them without a reason. Thanks in advance.

[Oreyca]

Re: Samsung UN40ES6100 no backlight

...see last post. I also checked voltage at c9110 and C9111, both read in the 250V DC range. I did notice with CNL802 disconnected that voltage on pins 2 and 3 (R+) were the same as with connecter plugged in (105V at start, then climbs to 250ish). However pin 7 (L+) is 0V at all times with connecter unplugged. So this is kind of throwing me. The 250V readings at C9110 and C9111 as well as the 250V readings at pins 2 and 3 (R+) sound like it indicates a problem with the load (LED strip) from what I have read. On the other hand the 0V reading at pin 7 (L+) with CNL802 disconnected sounds like it indicates a problem with the board from what I have read. Are these conclusions incorrect or might I have two problems? I also should note that for 6 month to a year before the TV went black there was at least one LED with issues on the upper RH side if the screen. Sometimes it would work normal, sometimes it would flicker and sometime it would just be a dim spot. Thanks again in advance for any support that anyone may be able to offer.

[budm]

Re: Samsung UN40ES6100 no backlight

You have open circuit in the LED string.

[Oreyca]

Re: Samsung UN40ES6100 no backlight

Thanks budm. Should the L+, No Load Voltage be 0V DC? It may not happen quick but I will update after repair is completed/attempted, if parts are even available. Thanks again.

[Oreyca]

Re: Samsung UN40ES6100 no backlight

I assume the open in the string will most likely be a open LED. If that is in fact true, could I remove the faulty LED from the string and solder in a jumper?

[budm]

Re: Samsung UN40ES6100 no backlight

Thanks budm. Should the L+, No Load Voltage be 0V DC? It may not happen quick but I will update after repair is completed/attempted, if parts are even available. Thanks again.

The two LED strings are connected in series, the first string 'R' has the R+ (Anode) connected to the boosted output of the power supply, the R- (Cathode) is then connected to the L+ (Anode of the 'L' string), the L - (Cathode) is the return line that is connected to the PWM controlled power MOSFET and the current sensing resistor.

So you get no reading on the L+ that means R LED string has open circuit.
You may be able to jump ONE LED and the circuit may be able to tolerate that without going into over current shut down protection, you can turn down the backlights level down as low as you can after the bypass/repair, but best to get the LED string and always turn down the backlights level.

[Oreyca]

Re: Samsung UN40ES6100 no backlight

Thanks for the circuit explanation and insight on the bypass budm. I thought an overcurrent protection mode might be a problem with the bypass. I will save the bypass as a last resort. I will keep looking for replacement strings but initially was not finding any new ones available. I may have seen a set of strings used on ebay. Perhaps that's the route I will need to take. I suppose if nothing else, the used strings will provide a source of extra LEDs that I can salvage if the used strings are not 100% either. Thanks so much!

[Oreyca]

Re: Samsung UN40ES6100 no backlight

I got my UN40ES6100 working again. I removed the RH LED string and found several obvious problems. Problem 1: One LED on the lower portion of the string had a burn mark on the face, it was open. Problem 2: Three LEDS on the upper portion had the plastic exterior of the LED flaking off. Used multimeter in diode mode and found two off the three were open. Also noticed that on most, if not all the LEDs, the plastic exterior was at least cracked on the backside (fine cracks, not severe). On all three of the open LEDs, I carefully stripped the plastic exterior off of them. Under the exterior there were two terminals with a fine gap between them (see pictures). I simply joined the two terminals with a dab of solder. I re-assembled RH LED string into TV and checked operation. Presto, LEDS were on. The full LH string operates. On the RH string, obviously the three LEDS I soldered did not illuminate but there were also two or three others that did not light either but had no real obvious signs of damage. Since they were not preventing the entire backlight from working I did nothing with them at this time. I reassembled the TV fully, turned backlighting setting down to 2 and it has been working for about an hour and a half now. I assume this fix will only be temporary since there were obvious problems with other LEDs, it's only a matter of time before a couple more go open. For this reason I will keep looking for replacement strings to be in stock and get them when they are. I will probably wait for it to fail again before installing them. Budm: I sent some money to your PayPal to say thanks.

[thoma]

Re: Samsung UN40ES6100 no backlight

http://www.kenotrontv.ru/forum/files...7-bn44-00620a/


http://www.electronica-pt.com/esquem...ng-smps-29728/

http://www.electronica-pt.com/esquem...ng-smps-29727/

http://www.electronica-pt.com/esquem...40d5003-29726/

[dsc]

Re: Samsung UN40ES6100 no backlight

After a delivery delay and some time off I finally got around to installing the new led strips and giving them a quick test. I must say they shine brighter than a newly polished 57 Chevy bumper.
I'll assemble the set tonight and give it a full test.
Now I've got a bunch of LED's as spares incase I run into another set or want to make something.

[budm]

Re: Samsung UN40ES6100 no backlight

Make sure to turn down the Backlights level as low as you can.

[dsc]

Re: Samsung UN40ES6100 no backlight

Will do.
I'll have to go back in and reset the diffuser, got a few led's showing up on the edge but otherwise it is working.
The cable port does't seem to work but the HDMI parts do.

[dsc]

Re: Samsung UN40ES6100 no backlight

So I've been testing the set out, for the most part it is a functioning set however, and there is always a however, I have some LED's showing up on the right edge, even after checking the placement of the diffusers and such, and when I connect the A/V composite I only get black and white.
I found a bad solder joint on the cable IN so that is now working fine but I would like to hook up the DVD.
Any suggestions?

[dsc]

Re: Samsung UN40ES6100 no backlight

Sorry, component not composite.

[Iamwally]

Ok, so I checked the voltages again and they are all over the place, as in I can't get a steady reading.
Drops to .003 then rockets to 1.5+ sometimes as high as 5. on both pins 2 and 6.
All I did was install a new IC9101.
Any chance that someone knows where I can find a reference for the blinking code?
DSC

Do you happen to have the part number for ic9101? Trying to fix a bn44-00502a out of a UN46ES6150FXZA with no backlights but everything else seems good.

Thanks,

John

[SJKME]

Re: Samsung UN40ES6100 no backlight

If you pull out the cable between the main board and the power supply, plug into the AC outlet but the backlights are still not on, then you have bad IC as freakaftr8 as suggested, or possible LED problem.

hi, i have the same problem and when i disconnected the cable from the main board to the power supply i still do not get back lights. my problem is that i have looked all over the power supply board and do not see the IC 9101 chip that needs to be changed. can you please tell me where it is located?

[nomoresonys]

Re: Samsung UN40ES6100 no backlight

http://www.shopjimmy.com/samsung-bn4...led-board.htm# Check the bottom side.

[NPB]

Re: Samsung UN40ES6100 no backlight

Hi Guys. Looks like it's been a while since the last post on this subject so I guess my old set hung in there longer than most. Maybe because I had previously turned the backlight down on all my sets.
I have a UN40ES6100, assembled in 2012, also with no backlight. Sound works and a picture can be seen with a flashlight test. Based on prior posts I think I have narrowed down the issue to either the Power Supply board or LED strips (suspect LED strips). If power supply I’d guess the IC9101. I checked voltage at C9110 and C9111, both read in the 250V – 270V DC range.
My primary question is if I’m reading the voltages on the CNL802 LED connector correctly and if the voltages are correct. I assume if they are then one or both of the LED strips are the likely culprits. CNL802 has 2 black wires coming from the LED strips on the left connecting to Pins 10 (L-) & 9 (both labeled “L-“ and both measure ~1-2VDC). 2 white wires coming at pins 7 (L+) & 5 (R-). Pin 7 measures ~190VDC and Pin 5 measures ~220VDC. 2 blue wires coming at pins 3 (R+) & 2 (R+). Pin 3 measures ~250VDC and Pin 2 measures ~250VDC.
Do these measured voltages look correct? If so, then I assume the LED strips are getting what they need to light and the trouble is one or more burnt individual diodes in the series.
Thanks so much. You guys provide a great service.