Insignia ns32d201na14 - TV works, no backlight

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

Have you checked D602 and V603 which looks as though they may have heated up the bottom of the board.

I'd be happy to check those two components. One is just a diode, so that should be pretty easy to check. The other one is what, a transistor? Not sure how to test that one.

[dick_barton]

Re: Insignia ns32d201na14 - TV works, no backlight

I'd be happy to check those two components. One is just a diode, so that should be pretty easy to check. The other one is what, a transistor? Not sure how to test that one.

You need to tell us since the details on it cannot be read from the picture.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

I believe it's a 6m240 chip.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

BUMP. Anyone else have anything? I think I might just replace the inverter pcb and see what happens.

[budm]

Re: Insignia ns32d201na14 - TV works, no backlight

At this point I am leaning toward bad LEDs.
https://www.badcaps.net/forum/showthread.php?t=56782

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

I was afraid you might say that. Time to open the panel, I guess. I'm in this far, might as well keep going.

Before I undertake this, how small are these LED's we're talking about here? I've got some pretty fine soldering tools, but I'm not really set up for SMD stuff. With a flux pen and a fine tip I'm sure just about anything can be accomplished, but I I'm not taking on something that's 2mm small.

[budm]

Re: Insignia ns32d201na14 - TV works, no backlight

Reece has some videos on you tube.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

Pulled apart the panel last night - was pretty tricky getting the LCD panel control board unstuck from the back of the panel case. Damn double stick tape. Finally broke it free and was able to remove the LCD and took off the frame and reflector. 3 rows of LED strips, 6 lights each.

Tonight I'll wire up a quick bulb tester using a pair of AA batteries and some sharp probes. I'll test each bulb to track down the shorted / open diode.

Once I narrow down which LED's are bad, where's the best place to get them?

[budm]

Re: Insignia ns32d201na14 - TV works, no backlight

Do not connect the 3V battery directly to the LED unless you know which pin is Cathode and which pin is Anode first otherwise you can damage the good LED due to the protection diode that is connected in anti-parallel with the LED, that conduction diode will conduct lots of current when you apply the Voltage in the reverse bias to the LED.
I always is power supply with current limiter set to about 50mA.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

What about a 2032 coin battery? Would that work for testing? Max power on that is only about 200 milliamps or so. Much less than a pair of AA batteries.

[budm]

Re: Insignia ns32d201na14 - TV works, no backlight

Use 100 Ohms resistor in series with the battery first to allow you to identify the LED ANODE/CATHODE pins first.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

Use 100 Ohms resistor in series with the battery first to allow you to identify the LED ANODE/CATHODE pins first.

Can do. I'll report back with results.

[ReeceyBurger123]

Re: Insignia ns32d201na14 - TV works, no backlight

Use your multimeter in diode mode its enough to light them very dimly.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

Use your multimeter in diode mode its enough to light them very dimly.

Thanks for the tip Reece! I'll give that a go.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

Thanks for the tip Reece! I'll give that a go.

Okay....we've made some progress here. Using the diode function on my meter, I was able to test each of the LEDs on the 3 strips, hoping to find one that would NOT illuminate during diode testing. First two strips, all bulbs lit up no problems. One the last strip though, the LED closest to the connector would not light up no matter how hard I tried to get it to go. I double checked my connection methods on the other two strips just to make sure I was checking right - nope, no light on that bulb.

So, I believe I've tracked down the problem - a shorted or open LED.

Next steps? Should I order a replacement and solder that on? Or should I try the stacking method that Reece has showed in his video?

This LED is pretty close to the connector, so there's not a lot of room for stacking on the side near the connector, but it might be possible.

Otherwise, where's the best place to buy new LEDs? Or maybe I could find someone who has either a replacement strip or part of one?

[ReeceyBurger123]

Re: Insignia ns32d201na14 - TV works, no backlight

Nice find, the led is open if it was shorted the meter would show 0 ohms or beep, with shorted Leds the backlight will actually be fine but if they fail open backlight is dead instantly. Also yes you can use my method for this whichever is easiest

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

Anyone have a few LED's they'll sell me to mail in a greeting card? Seems kind of pointless for me to spend $15-20 on 100's of LED's that I'll never use.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

Anyone have a few LED's they'll sell me to mail in a greeting card? Seems kind of pointless for me to spend $15-20 on 100's of LED's that I'll never use.

Does anyone know where I can buy replacement LED's for this TV? I just need 2-3.

[ReeceyBurger123]

Re: Insignia ns32d201na14 - TV works, no backlight

Buy smashed Tv and use stacking method.

[smalltownguy]

Re: Insignia ns32d201na14 - TV works, no backlight

Contacted the good folks at Cedar Grove TV in Eagan, MN. They sent me out a few LED's to tinker with. I was able to remove the failed LED from the strip and solder in a replacement. I decided to use a combination of the stacking method and the direct replacement. I completely removed the old LED, put down some electrical tape as a barrier, scratched some solder pads, and soldered jumpers. Then I glued the diffuser back on top. Success! She lives again!

Much appreciation to all of you who chimed in to assist. In the end, it wasn't bad caps, but still, the diagnosis here was top notch.