EU55JS9000T black screen and sound good

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Above is from your training pdf, there's pictures there too.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

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.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

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

[nomoresonys]

Re: EU55JS9000T black screen and sound good

I agree with you.
This short circuit capacitor is suspicious but I don't know where the origin is. There are definitely voltages on all the inductors, however I don't know if they are all correct.

To check if there is an image I planned to disconnect the PWM signals from the TCON board to inject a voltage of 1V directly onto the backlight control board. What do you think about this test and should a DC voltage be injected?

I'm not sure how that works.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

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

[totof]

Re: EU55JS9000T black screen and sound good

Sometimes it can be the components in a circuit that can make things seem shorted, like if there's a resistor in circuit across it, it may read short and be ok, that's why you get the best results off the board.

I agree with you.
This short circuit capacitor is suspicious but I don't know where the origin is. There are definitely voltages on all the inductors, however I don't know if they are all correct.

To check if there is an image I planned to disconnect the PWM signals from the TCON board to inject a voltage of 1V directly onto the backlight control board. What do you think about this test and should a DC voltage be injected?

[nomoresonys]

Re: EU55JS9000T black screen and sound good

https://www.ebay.co.uk/p/12061435673

[nomoresonys]

Re: EU55JS9000T black screen and sound good

It's too bad that you don't have another tv to try that ocb on.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Another thing that's easy to try if those things your looking at check out ok, is take connector CN301 and CN801 off and try it, will be no wifi or sound of course. just wondering if that bit of less power required would make a difference, then would maybe have a better idea of where to look.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Sometimes it can be the components in a circuit that can make things seem shorted, like if there's a resistor in circuit across it, it may read short and be ok, that's why you get the best results off the board.

[totof]

Re: EU55JS9000T black screen and sound good

I would take the board out of the box and look it over closely from all sides, check for bad solder joints etc.

I've done this before but didn't see anything unusual.
Without a diagram it's shit

[nomoresonys]

Re: EU55JS9000T black screen and sound good

I would take the board out of the box and look it over closely from all sides, check for bad solder joints etc.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

If your meter is not auto-ranging you will probably need to adjust the ohm mode to the different settings and see if you get a reading, OL can just mean that your meter isn't set right.

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Read the cap in ohm mode, make sure you have good connection with the probes.

[totof]

Re: EU55JS9000T black screen and sound good

The pads of the capacitor is still shorted.
With the multimeter I read OL for this capacitor, she is not dead.
Alas, I would have loved it if she was the one to be hs

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Ok, now hopefully the capacitor is still off the board, check the pads it came off of, does it read short? maybe also check it in ohm mode.

[totof]

Re: EU55JS9000T black screen and sound good

Yes, I had done this test. 0.74V in one direction and OL in the other direction

[nomoresonys]

Re: EU55JS9000T black screen and sound good

Use a multimeter. Diode mode meter connected in one direction get a voltage drop zeners are usually about .6 volts, meter leads switched and you get OL, 1.

[totof]

Re: EU55JS9000T black screen and sound good

So what did it read?

Sorry I don't understand your question

[nomoresonys]

Re: EU55JS9000T black screen and sound good

So what did it read?