Philips TV Backlight Repair

[chestercc]

So i'm trying to replace the LED's in a Philips TV. It's 42" with a 715g7262-p01-000-0010 backlight driver board based around an O2 Micro OZ9902CGN.

My issue is when I replace all the LED's on one board with the new 3V 300ma ones they immediately burn out when the set is powered again. I previously tried the same thing with 6V LED's and the backlight flickered for a bit but wouldn't start.

The original LED's which I removed which are still working start to melt and burn when given more than 3V on DCPS so I know they shouldn't be higher voltage ones.

I have one original backlight strip which just had two bad LED's on it and I replaced these two bad LED's with the 6V ones and it worked for a little bit then the new 6V LED's started to smoke and they burned as well. The original LEDs on this backlight strip are still good.

The backlight strips are LB43003 which I could get a whole set of but for £60 it simply isn't worth it for the value of the TV.

I'm presuming that the original LED's are higher current and the backlight driver is working in constant current mode and is driving the new led's too hard. I would appreciate some advice on what I need to modify on the backlight driver board to reduce the current output.

[nomoresonys]

Re: Philips TV Backlight Repair

Usually done with a resistor mod, maybe checkout TomTechTod on youtube, maybe leave a comment on one of his videos telling him what model you have, he may be able to walk you thru it.

[Rajnhl]

Re: Philips TV Backlight Repair

check mosfet connected to cathode of lamps (Q802) for short . there are few resistors connected to source of this mosfet connected to ground. they are 1.1 ohms never bypass them. source of mosfet is also connected to current sense pin 9 of oz9902 through 1k resister. check this resister also for open.

[nomoresonys]

Re: Philips TV Backlight Repair

the topic concerns bringing down the current, done with resistor mod, has nothing to do with bypassing anything.