PHILIPS 40PFL3008H led backlight repair

[daroo]

Hi, I have this tv with the backlight that doesn't work. It's a vestel set.

I've opened it and found three bad leds. I've replaced them with 3 led from a 3528 led strip.

Now every led lights up but the brightness is very low and slowly fade away (20 sec)

How can i solve this problem? maybe i can put a small resistor near the new led that I have replaced? because I think that it hasn't enough resistance

I wouldn't like to buy new tv led strip because this tv is crap and it's not worth it

Sorry for my bad english

[budm]

Re: PHILIPS 40PFL3008H led backlight repair

Are the ORIGINAL LEDs 3V Vf or 6V Vf? What is the replacement LEDs, 6V Vf or 3V Vf?

[daroo]

Re: PHILIPS 40PFL3008H led backlight repair

I'm quite sure that originals are 3V,

i don't know about the replacement leds from the strip, I know that the strip can be cutted and powered with 12volt every 3 leds.

At the moment I have installed (to replace the original led burnt) a Led from the strip with the resitor (with 151 written on it) because without that restistor the new led burns immediately.

[budm]

Re: PHILIPS 40PFL3008H led backlight repair

Well those LEDs on the replacement strip are NOT made to handle 200~400mA, I doubt that since 3 LED per section so total Vf is about 9V, that leaves about 3V vdrops on the 150 Ohms current limit resistor which the current for the LEDs is limited to 3V/150 Ohms = 20mA (0.02A), so no wonder those replacement LEDs blew up!
You need 1W rating LED!

[daroo]

Re: PHILIPS 40PFL3008H led backlight repair

Well those LEDs on the replacement strip are NOT made to handle 200~400mA, I doubt that since 3 LED per section so total Vf is about 9V, that leaves about 3V vdrops on the 150 Ohms current limit resistor which the current for the LEDs is limited to 3V/150 Ohms = 20mA (0.02A), so no wonder those replacement LEDs blew up!
You need 1W rating LED!

so my leds can not handle the TV current...is there another cheap solution I can try for the moment? adding a resistor? totally removing the 3 leds?

I don't need peerfection

[dick_barton]

Re: PHILIPS 40PFL3008H led backlight repair

If you don't replace them with suitable leds then it is highly probably that more and more will fail very quickly.
You could by a led strip for your set and do a stacking method or replace the faulty ones with ones from the strip.
If you search the forum you will find information on both methods.

[ReeceyBurger123]

Re: PHILIPS 40PFL3008H led backlight repair

Or you could just bridge them over/short out the pads. Will keep it going its a Vestel with sammy panel they dont last long trust me. Also you can find the strips for VES400 panels all over ebay cheap apso just steal the Leds off them.

[daroo]

Re: PHILIPS 40PFL3008H led backlight repair

Or you could just bridge them over/short out the pads. Will keep it going its a Vestel with sammy panel they dont last long trust me. Also you can find the strips for VES400 panels all over ebay cheap apso just steal the Leds off them.

Thanks for your advice,
If I just bridge the pads and set the brightness of the tv on low, will the other leds burn easily, or the panel will be just a little bit uneven?

[daroo]

Re: PHILIPS 40PFL3008H led backlight repair

I've short out the pads and now the tv works great! i have set the backlight to low and updated the firmware.
Thanks

[ReeceyBurger123]

Re: PHILIPS 40PFL3008H led backlight repair

Lol will keep going for a little while longer till the Psu fails