Samsung le40n71b goes black after 2 sec

[tom66]

Re: Samsung le40n71b goes black after 2 sec

The combined company, since dissolved into Samsung, was known as S-LCD.
The "LF" style logo on some Samsung boards means "Lead-Free"

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

You have to remove the LD wiree from the inverter board connector first and then use 1K resistor between the 13V and the LD wire that you just remove from the connector.
SONY and SAMSUNG were working together on the TV design. You will see SONY/SAMSUNG 'S' I forget the name of the two companies use. I look for SAMSUNG Training but did not find the one for this chassis.

I do not understand how you mean.
In what way to direct the power?
What will happen if I just put a jumper without disconnecting anything

[budm]

Re: Samsung le40n71b goes black after 2 sec

The small connector on the Balancer board, you have the connector with pin labeled with LD, you need to remove just that wire from the connector, then you use 1K resistor between the 13V pin and the wire that you just remove.

"What will happen if I just put a jumper without disconnecting anything" You will damage the comparator IC on the balancer board.

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

The small connector on the Balancer board, you have the connector with pin labeled with LD, you need to remove just that wire from the connector, then you use 1K resistor between the 13V pin and the wire that you just remove.

"What will happen if I just put a jumper without disconnecting anything" You will damage the comparator IC on the balancer board.

Hello again. Sorry for the late reply. I have been away on at her things.
Anyway I disconnected the LD wire pin on the in the connector and put the 1K resistor between 13V and the LD wire but it was no difference.
You wrote two different things.
"Remove wire from inverterboard" and
"Remove wire from balancerboard"
The resistor is supposed to be between 13V and LD-pin in to inverterboard with LD wire removed right?
Any new suggestions.

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

Hello again. Sorry for the late reply. I have been away on at her things.
Anyway I disconnected the LD wire pin on the in the connector and put the 1K resistor between 13V and the LD wire but it was no difference.
You wrote two different things.
"Remove wire from inverterboard" and
"Remove wire from balancerboard"
The resistor is supposed to be between 13V and LD-pin in to inverterboard with LD wire removed right?
Any new suggestions.

up

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

up

Up

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

Someone please help

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

Hello again. I'm back from lots of work and other things.
Now I have done some more testing and actually got the set to stay on.
I did like the suggestion. It stays on if I do like photo 1 but not in photo 2.
Why is what ? Isn't it the same thing?

edit: haha I see on the photo that I did not do as he suggested and that it is not the same thing in the pictures. The cable switched color on the connector half the way on the end LD is black. Anyway that worked
now what ?
Anyway what do I do now?
What component is wrong?

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

Up

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

Up

Is it anyone who have a thought about what can be wrong.
Can it be to low current on the 13V ? because it obviously
works with the 13V and LD with the resistor between when the 13V is not powering anything else

[budm]

Re: Samsung le40n71b goes black after 2 sec

Hello again. I'm back from lots of work and other things.
Now I have done some more testing and actually got the set to stay on.
I did like the suggestion. It stays on if I do like photo 1 but not in photo 2.
Why is what ? Isn't it the same thing?

edit: haha I see on the photo that I did not do as he suggested and that it is not the same thing in the pictures. The cable switched color on the connector half the way on the end LD is black. Anyway that worked
now what ?
Anyway what do I do now?
What component is wrong?

So by pulling up the LD line high the lamps stay on, so it either the comparator circuit on the Balancer board is bad or it does detect the fault of the bad lamps. You do see even light on the screen when it has white scene? I think at this point I believe you have at least one bad lamp.

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

So by pulling up the LD line high the lamps stay on, so it either the comparator circuit on the Balancer board is bad or it does detect the fault of the bad lamps. You do see even light on the screen when it has white scene? I think at this point I believe you have at least one bad lamp.

I do not now if it has a difference but it was not the LD line I pulled.
If you look in the first photo in post 569952 ( my last with photo )
I pulled the 13V cable out of the connector and put the resistor between the 13V cable i pulled and LD still on the balancerboard. (I pulled the wrong cable as it switched color on the way to the balancerboard)
But by doing wrong I made it stay on
If I do like you suggested earlier
"The small connector on the Balancer board, you have the connector with pin labeled with LD, you need to remove just that wire from the connector, then you use 1K resistor between the 13V pin and the wire that you just remove."

That does not work. That was why I thought it might be to low current on the 13V, because it does not power anything else than the LD-line back like I did? Just a thought.

[budm]

Re: Samsung le40n71b goes black after 2 sec

"I pulled the 13V cable out of the connector and put the resistor between the 13V cable i pulled and LD still on the balancerboard. (I pulled the wrong cable as it switched color on the way to the balancerboard)
But by doing wrong I made it stay on" By pulling the 13V line out off the connector, that means the comparator circuit on the Balancer board no longer gets the 13V to run but the LD will have >11V signal that goes back to the main board to think the LAMPS are OK.
The 13V is used for running the ICs on the BALANCER board. I do not know why what I suggested did not work since that is how I do it to fool the circuit that the lamps are OK, then I look at the screen using white scene to so if i can notice any dark horizontal band on the screen which will indicate that the lamp is not on.

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

" By pulling the 13V line out off the connector, that means the comparator circuit on the Balancer board no longer gets the 13V to run but the LD will have >11V signal that goes back to the main board to think the LAMPS are OK.
The 13V is used for running the ICs on the BALANCER board. I do not know why what I suggested did not work since that is how I do it to fool the circuit that the lamps are OK, then I look at the screen using white scene to so if i can notice any dark horizontal band on the screen which will indicate that the lamp is not on.

I thought that the comparator circuit on the Balancer board might be using to much of the power when the 13V is still connected there, and that is why what I did is working.
Anyway I will try to see in the white screen if I see a black line.
Thanks so much for all help so far.
Best regards nalle077

[budm]

Re: Samsung le40n71b goes black after 2 sec

Does the 13V pin stay around 13V or it drops way down?

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

Does the 13V pin stay around 13V or it drops way down?

The 13V stays on about 14.5V
I see now when I trick it like I did before that it is a dark horizontal line just where I saw it was darker earlier.
It is a photo of it some post ago.
So now I know it is a bad tube.
what are the options?
Can I use the set like this without the comparator circuit?
What can happen?
I don't think it should be a problem for me to change the tube, but I don't think it is worth it to buy one and post it to Sweden.
I can change it when I found a 40" on the scrap or get one with a cracked screen.

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

The 13V stays on about 14.5V
I see now when I trick it like I did before that it is a dark horizontal line just where I saw it was darker earlier.
It is a photo of it some post ago.
So now I know it is a bad tube.
what are the options?
Can I use the set like this without the comparator circuit?
What can happen?
I don't think it should be a problem for me to change the tube, but I don't think it is worth it to buy one and post it to Sweden.
I can change it when I found a 40" on the scrap or get one with a cracked screen.

up

[budm]

Re: Samsung le40n71b goes black after 2 sec

You can bypass the balancer transformer for that lamp.
https://www.badcaps.net/forum/showpo...6&postcount=16

There must something wrong in the measurement you made earlier, it should have shown big spike on the diode for detection of that bad lamp.

[nalle077]

Re: Samsung le40n71b goes black after 2 sec

You can bypass the balancer transformer for that lamp.
https://www.badcaps.net/forum/showpo...6&postcount=16

There must something wrong in the measurement you made earlier, it should have shown big spike on the diode for detection of that bad lamp.

Do you mean like he does in the video?
I did like him. As I wrote earlier it seems like 1 transformer goes to 2 tubes in my set.