backlight issue Samsung UE32EH5000

[Dannyx]

Re: backlight issue Samsung UE32EH5000

Ok guys update: replaced the IC on mine but it still doesn't turn on....this is getting rather annoying TBH....

[Dannyx]

Re: backlight issue Samsung UE32EH5000

Update no. 2: I wanted to give replacing the caps a shot and when I removed CM867, I was surprised to see it actually leaked through one of its legs, so I DID have a faulty cap after all, despite showing no signs of bulging at all. I replaced it and now the voltage stays down to a more acceptable 123v on the blue wires, but the backlight STILL doesn't turn on. Another thing I noticed is that I'm now also missing some voltages on the IC: REF is 0 and so is ADIM...definitely not OK. No shorts on those pins, so perhaps the IC got busted during the soldering phase...may have blasted it a bit too much with hot air, though I doubt it..

[dick_barton]

Re: backlight issue Samsung UE32EH5000

The Ref is an output derived internally from VCC so have you checked once again that the VCC for the IC is still there?

[Dannyx]

Re: backlight issue Samsung UE32EH5000

TV is working now: realising the new IC is most likely faulty since it no longer generated its REF output, I ended up putting back the original SLC (the one I thought was faulty all along) and along with the replaced caps the backlight came on The new IC either got damaged during soldering (which I doubt, because the original one survived not one, but TWO rounds of soldering), or due to overvoltage cause by the faulty cap (remember, the voltage went to 230 something volts !). Still, this doesn't explain how the original is still working after all that ordeal, but NVM. Another reason might be that the new IC I got is a FAN7430, which is supposed to be a direct replacement for the SLC, but perhaps there are some minor difference it didn't like.... Either way, it's solved, so Mikeyboy2007 if you're still watching this thread, consider replacing the two 33 and 47uf caps on the backlight booster and you should be good, given you have no other issues with the LEDs themselves.

[budm]

Re: backlight issue Samsung UE32EH5000

Another bad SAMWA cap. Good job finding the bad cap. So what is the DCV rating of that 47uF cap? That cap is for filtering the DC to feed the Boost converter circuit and I expect the Voltage to be low and with lots of AC ripple so I did not expect the boost converter to be working and putting out over 270V. I also expect the backlights to flash on for second before the shutdown happen if it is due to bad AC ripple.

[Dannyx]

Re: backlight issue Samsung UE32EH5000

Another bad SAMWA cap. Good job finding the bad cap. So what is the DCV rating of that 47uF cap? That cap is for filtering the DC to feed the Boost converter circuit and I expect the Voltage to be low and with lots of AC ripple so I did not expect the boost converter to be working and putting out over 270V. I also expect the backlights to flash on for second before the shutdown happen if it is due to bad AC ripple.

The original was rated for 200v, but I always go one step higher, so I put in a 250v one.

[Doc38343]

Re: backlight issue Samsung UE32EH5000

Well done fellas!!
Taught me a thing or two... thanks!

[Mikeyboy2007]

Re: backlight issue Samsung UE32EH5000

@Dannyx i still have no luck. replaced it with another controller and still have same issue. anyone else having any luck ?

[Dannyx]

Re: backlight issue Samsung UE32EH5000

@Dannyx i still have no luck. replaced it with another controller and still have same issue. anyone else having any luck ?

Willing to help you fix this sucka, but please refresh my memory as to what you already did: LEDs ok ? Caps OK ? New IC ? At least you're not going against the clock, unlike me when I had to fix mine for a client

[Mikeyboy2007]

Re: backlight issue Samsung UE32EH5000

just seen on previous post there Dannyx to replace caps, i also swapped it for the fan controller and i have no issues with LED themselves. will replace caps and report back thanks

[Mikeyboy2007]

Re: backlight issue Samsung UE32EH5000

@Dannyx i swapped out the 47uf cap and it made no difference. i am going to test voltages again. i did however swap out same cap on same board in a 40 inch Samsung and it brought the backlights on. so must be a common fault with these boards. like you is wapped it from 200v to 250v.