Samsung curved UE55H8005 no picture

[budm]

Re: Samsung curved UE55H8005 no picture

But the backlights still come on if the small connector (for the four PWM control signals) on the T-Con is disconnected?

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

Actually, the backlights come on just as it should when all connectors are seated.
So I haven't done a test to disconnect the PWM connector. (that's how it went into smoke last time)
I would like to know the meaning of the 3 T-CON leds.
One is for showing fuse is OK. But the other two is unknown. The second led turns on upon starting up TV but goes out after a few seconds

[Diah]

Re: Samsung curved UE55H8005 no picture

Man, you have edge LED, those always if one defect the whole strip will just light on at start up. then all goes out and give error code, the reset depending on the TV circuit design how it handle this error, some TV turn off whole set, some just turn off backlight, and this under your hand likely turn off picture ( T-CON ) because useless as no back light.

you have 3 LED , one near Fuse this is power. the next to left backlight detect. and the last one left side belong to panel. so which are stay one beside the one near the fuse?

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

After replace T-CON backlight is constant on

The led by the fuse constant on. See pic attachment for other two leds behaviour.

I tried to enter both T-CON pattern generation and mainboard pattern generation, none gives a picture

[Diah]

Re: Samsung curved UE55H8005 no picture

interesting.. i may wrong too.. however plug out the 2 panel ribbon and turn on.. let see which led will light on.

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

interesting.. i may wrong too.. however plug out the 2 panel ribbon and turn on.. let see which led will light on.

The same two leds will light with the only difference none will go out.
Both leds on constant.
But I have never seen the 3rd led on.

Panel failure ?

Could still be a mainboard problem - since T-CON testmode is controlled by MUTE 3-6-9 (mainboard handled)
Is there a jumper-activated testmode on T-CON also ?

BTW - tried MUTE 4-1-9-EXIT which is supposed to be a backlight test sequence start. Does not respond to that either.

[Diah]

Re: Samsung curved UE55H8005 no picture

The same two leds will light with the only difference none will go out.
Both leds on constant.
But I have never seen the 3rd led on.

Panel failure ?

Could still be a mainboard problem - since T-CON testmode is controlled by MUTE 3-6-9 (mainboard handled)
Is there a jumper-activated testmode on T-CON also ?

BTW - tried MUTE 4-1-9-EXIT which is supposed to be a backlight test sequence start. Does not respond to that either.

its early to make judgment on panel fault.
also now as your photo the Led at the middle remain out which located ( between ) the first near fuse and the one close to the panel , and the other remain on .. then need to do other test

put back the panel ribbon to T-CON and just the back light sockets the white and blue take them out from PWB and turn on.. notice the led on T-CON ( the thirs one if go on or not ) or f the set give error ( don't start ) and if it start give signal to hear voice and spot light to the screen to explorer any image on it.

if the third remain off the the one was go off after while do the same,, then need to take the panel side cover and inspect of liquid / water damage first on the panel taps

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

If take away blue and white backlight ribbon from PSU, leds on T-CON does not change.

Fuse indicator led ON
Second led on for a few seconds - then off
3rd led always off

Please note that set never goes into protect or standby. Sound on HDMI is present and channels and volume switching is possible.

[Diah]

Re: Samsung curved UE55H8005 no picture

Fuse indicator led ON
Second led on for a few seconds - then off
3rd led always off.

please check your statement here with photo you post before post #44 ... there are different on led position when you did panel out and when backlight out !!

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

I think it's just a misunderstanding

Summary of tests:

1. Remove panel ribbons and have backlight connected to PWB: The led in picture (post #44) is constant on + fuse led constant on.
This led is closest to the panel ribbons
The led "in between" off

2. Remove backlight ribbons (blue and white) and have panel ribbons connected, then the very same led closest to panel ribbons turns on for two seconds, then off
Fuse led constant on
The led in between off (and has always been)

[Diah]

Re: Samsung curved UE55H8005 no picture

also the middle one always off..
we dont know if the T-CON you replaced was full working one.. and you cant test it as no other set under hand.
you need to seprated one panel ribbon cable to mark which one the third LEd remain on and if there half picture or line.. if this dont help
then in this condition i will take the screen in part ,
1- to be sure all LEd backlight going on.
2-to inspect the panel taps if there damage as we know from cleaning etc.
other will be just lost time for you.

if those you wont like . then replace the fuse on the bad T-CON and put it in place to compare the condition.

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

If there was a problem in the backlight circuitry I would assume the set go into protect and disable backlight?
The T-CON was brand new delivered by Samsung, but of course it can be faulty anyway (because with old T-CON the PWM dimming was making the backlight turn off, with new T-CON it stays on)

Is there a chance for mainboard failure?
Maybe the middle led is indicating proper LVDS recieved, and if not mainboard is sending out, led will not light? Just a thought.

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

Samsung suggested a replacement T-CON module which will come today.
It appeared the first replacement was faulty.

Update soon

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

Sadly enough there are no difference with the new T-CON.
Screen backlights turn on but no picture what so ever. Sound OK.

[dick_barton]

Re: Samsung curved UE55H8005 no picture

Have you access to an oscilloscope to check for LVDS signals?

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

The thing is that, this set has both T-CON and Mainboard testmode with pattern generation. It does not respond to either of the two.
The T-CON should be able to generate pattern even if LVDS is missing.

And strange enough, only T-CON fuse led is ON, the second led turns on for a few seconds during boot-up, the third led is off and has always been on both T-CON's.
All 3 leds should be ON according to service manual. And manual points out, if leds are not ON, T-CON is faulty, which I don't longer think since it has been replaced again.

To have the 2nd led stay on I have to remove one of the panel ribbons (doesn't matter which of the two)

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

LVDS output confirmed from mainboard. There are some i2C lines also in the ribbon between mainboard and T-CON but it's not any data on those lines, which makes me a bit confused.

It appears the mainboard does not work properly. Because: When trying to enter testmode sequence for backlight, the backlight does not go into testmode. (Changing zone dimming in a testmode sequence) Neither does T-CON produce test patterns.
This COULD be explained by a faulty mainboard not outputting correct communication to T-CON, since this board also controls the backlight dimming.

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

Summary:

Tried two new T-CON's with no improvment.
PSU is good.
So what's left now is either mainboard and/or panel.

In my world, things point towards the mainboard since all testmode is activated from mainboard by remote sequence. And it does not respond to any testmode.

[Roman_Ark]

Re: Samsung curved UE55H8005 no picture

Hi PowerAmpFreak,

I have exactly the same symptoms and already tried replacing the main board but that did not help.

Have you managed to solve the problem?

Thank you!

[PowerAmpFreak]

Re: Samsung curved UE55H8005 no picture

It was the panel

Samsung accepted to repair it under warranty after all