EU55JS9000T black screen and sound good

[Davi.p]

Re: EU55JS9000T black screen and sound good

not the main firmware but the spi one yes maybe

[totof]

Re: EU55JS9000T black screen and sound good

So what's up, is it solved or what?

No it's not solved (unfortunately)

Lotas, first post states sound is good, freetnt tv is audible, so no software problem for me...
as per diagram in post 82 Hawk N is responsible of driving TCON and therefore backlight levels, but there is also an SPI flash memory connected to it that can be polluted..

The TV works well, I can hear the sound from the TV (TNT tuner source). The sound comes about 10 seconds after plugging in the OCB cable.
So I don't think it's a firmware issue.

[Davi.p]

Re: EU55JS9000T black screen and sound good

Lotas, first post states sound is good, freetnt tv is audible, so no software problem for me...
as per diagram in post 82 Hawk N is responsible of driving TCON and therefore backlight levels, but there is also an SPI flash memory connected to it that can be polluted..

[nomoresonys]

Re: EU55JS9000T black screen and sound good

So what's up, is it solved or what?

[Diah]

Re: EU55JS9000T black screen and sound good

5 pages right now... and the answer was at POST #4 & #8

[lotas]

Re: EU55JS9000T black screen and sound good

Yes, I also thought about that, a bit like a certain laptop motherboard. This could be any component on the chain (Hawk-P, Hawk-US or Hawk-N)
The only thing that could make me think that it is something else is that the backlighting is cut off immediately after connecting the cable while the Hawk components have just been powered and are not yet initialized and operational.

Samsung has implemented this way, even on regular TVs, when the motherboard is disconnected, the backlight will be on constantly and when a faulty motherboard is connected, the backlight will go out, and here, like you, there may be a problem with the eMMC (the firmware cannot load).

[Davi.p]

Re: EU55JS9000T black screen and sound good

i cannot know the complex architecture of such a tv set due to the lack of manuals, but i guess the boot sequence and screen driving sequence is different if you connect the OCB at hot or at cold, i think on the back of tv there is a second main board with something like a subtitute cpu with few tasks..

[totof]

Re: EU55JS9000T black screen and sound good

I have few time now to read back all, but since inductors shows no apparent power supply problems, and the hawk p that is the main processor i think, and it is heating a bit, then probably there is cpu soldering problem, i think it is not sending image to the tcon, the tcon that controls backlight on the basis of the image content, sends an almost black signal level to it (see back the 0,04v on p dim)..

Yes, I also thought about that, a bit like a certain laptop motherboard. This could be any component on the chain (Hawk-P, Hawk-US or Hawk-N)
The only thing that could make me think that it is something else is that the backlighting is cut off immediately after connecting the cable while the Hawk components have just been powered and are not yet initialized and operational.

[Davi.p]

Re: EU55JS9000T black screen and sound good

I have few time now to read back all, but since inductors shows no apparent power supply problems, and the hawk p that is the main processor i think, and it is heating a bit, then probably there is cpu soldering problem, i think it is not sending image to the tcon, the tcon that controls backlight on the basis of the image content, sends an almost black signal level to it (see back the 0,04v on p dim)..

[nomoresonys]

Re: EU55JS9000T black screen and sound good

I don't like to but I give up, we seem to have a communication error.

[totof]

Re: EU55JS9000T black screen and sound good

Now read, check the other similar capacitors in the area, leave them in circuit, DO they also show OL??

Last week-end I have checked all capacitors on the data lanes of the ocb cable and all are good (100 nF). I have checked this capacitors on main board side and on ocd side.

Attached photo of the OCB board to the connector to the motherboard

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Now read, check the other similar capacitors in the area, leave them in circuit, DO they also show OL??

[totof]

Re: EU55JS9000T black screen and sound good

Why would a capacitor read OL?
If the capacitance value is within the measurement range, the multimeter will display the capacitor's value. It will display OL if a) the capacitance value is higher than the measurement range or b) the capacitor is faulty.

I read OL for capacitor in ohm mode, in capacitance mode I read 1 microfarad.

It's total waste of time and riskful to test backlight, since in Screen test everything works then your defect is 100% in the couple OCB+main board (let's call it so...)

Yes I agree with you.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Well if you already did a backlight test that passed, don't try anything experimental, like you described.

[Davi.p]

Re: EU55JS9000T black screen and sound good

It's total waste of time and riskful to test backlight, since in Screen test everything works then your defect is 100% in the couple OCB+main board (let's call it so...)

[nomoresonys]

Re: EU55JS9000T black screen and sound good

So if you are getting a reading, NOT OL on all your other capacitors, then that one is bad.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Why would a capacitor read OL?
If the capacitance value is within the measurement range, the multimeter will display the capacitor's value. It will display OL if a) the capacitance value is higher than the measurement range or b) the capacitor is faulty.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

https://www.youtube.com/watch?v=ymvyxlWdEck


https://www.youtube.com/watch?v=1QigP2qkv0M

[totof]

Re: EU55JS9000T black screen and sound good

My backlighting control board is not exactly the same as that in the document on post #1, the connectors are the same but the components are different.
At the terminals of the 16 diodes I measure 59V on one side and 20V on the other with the reference on the chassis.

[totof]

Re: EU55JS9000T black screen and sound good

Did you get a reading on that cap in ohm mode? test as in post #57.

OL in ohm mode on multimeter. No short cut.

I do see a backlight operation test in your training pdf from the first post.

Yes the backlighting works but it turns off immediately (<0.2 sec) as soon as the OCB cable is plugged in.
The P_DIM1..16 signals from TCON board falls to 0,36V, BL_ON is still good (4,7V)
The Tcon test works well (see post #22) but only when ocb is not connected

Testing Backlights
1. Remove CN803 (Main to SMPS) and CN9003
(Main to Micro Dimming Board) to activate Back Lights.
Both connectors must be removed to light backlights.
2. Check each of the 16 circled components above in each
L and R quadrants for approx. 95VDC by connecting the p
lus lead of the multi meter to either side as shown on left (
BB9101) and negative meter lead to chassis ground.
3. If any read high (approx 160VDC) a string of LED
Backlights are open (defective panel). If a voltage is low,
remove the LED panel connector & test again. If it stays
low replace defective SMPS.

OK, I will try this test