LG L1953S doesn't power on

[selldoor]

Re: LG L1953S doesn't power on

@ Tufi 979
Welcome to the forum-
We can help a lot more if you please post good clear pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

It will be useful if you can say a bit about yourself - skills tools etc.

[Joun]

Re: LG L1953S doesn't power on

Well I've got a new controller ic and replace the old one..I now have steady 12.3V and 5.4V.
The thing is the moment I plug VGA board it acts exactly as before: I have about 13V that are slowly dropping 'till it reaches zero.
I must add to that I have the 12.3 and 5.4 voltages only if I add load on 12V output by soldering a led string I have about half a meter long..If output is left without any load at all I have about 17volts which points out there is something very wrong with the power supply board, right?
The most strange of all is that just out of curiosity a have put the old ic back and it acts exactly the same with the new one..

[jetadm123]

Re: LG L1953S doesn't power on

Well I've got a new controller ic and replace the old one..I now have steady 12.3V and 5.4V.
The thing is the moment I plug VGA board it acts exactly as before: I have about 13V that are slowly dropping 'till it reaches zero.
I must add to that I have the 12.3 and 5.4 voltages only if I add load on 12V output by soldering a led string I have about half a meter long..If output is left without any load at all I have about 17volts which points out there is something very wrong with the power supply board, right?
The most strange of all is that just out of curiosity a have put the old ic back and it acts exactly the same with the new one..

While the 13V is dropping, what's happening with the 5V? Is it stable, dropping or at 0V?

The 17V under no load conditions is probably ok, since the 13V output is unregulated and will increase under no load conditions.

A good focused photo of your logic board would also be helpful.

[selldoor]

Re: LG L1953S doesn't power on

Last time round you got voltages when you lifted R111 did you ever check D102 to see if it was functioning correctly.

http://www.ehow.com/how_7556262_test-1n4007-diode.html

[Joun]

Re: LG L1953S doesn't power on

While the 13V is dropping, what's happening with the 5V? Is it stable, dropping or at 0V?

The 5volts output has 0V.But now after I replace the controller ic I have more or less normal output (12.3 at 12v and 5.4 at 5v) but as soon I connect Vga board, 12Volts starts to drop and 5Volts goes to 0. I have check Vga board with my magnifing lamp,everything looks fine.I have also measure for low resistance paths at 12V and 5V,didn't find any..

[Joun]

Re: LG L1953S doesn't power on

Last time round you got voltages when you lifted R111 did you ever check D102 to see if it was functioning correctly.

I have check it many times,it is working just fine..

[retiredcaps]

Re: LG L1953S doesn't power on

but as soon I connect Vga board, 12Volts starts to drop and 5Volts goes to 0.

Post a picture of the logic board.

It may or may not be your problem, but see (root cause in post #23)

https://www.badcaps.net/forum/showthread.php?p=114994

The monitor that I fixed is being used to type this.

[Joun]

Re: LG L1953S doesn't power on

I have read your post retiredcaps but it is not my case..
Voltages are dropping before I even connect ribbon cable at t-con,with only vga board connected.
I have just solder a 6.8K resistor between 5volts output and the on and dim pins of connector.So the CCFL are on without any problem but the 12V output drops at about 10V and leds I have connected at this output are flickering with a frequency of some tenths of Hz.
Is that a clear sign that the problem is at power supply or am I wrong?

[Joun]

Re: LG L1953S doesn't power on

^^ I have to add that if I unplug one or more CCFL's I got the classic " two seconds to black " symptoms so I guess inverter section works fine..

[selldoor]

Re: LG L1953S doesn't power on

Joun - can you go back to point where you said

"I have more or less normal output (12.3 at 12v and 5.4 at 5v)"

Was that just with the power board connected to the mains?
and are the voltages stable at that?
If you connect a load to either the 12 or 5 what do the voltages do?

You then said when you connect the vga board the voltage
drops out.

If voltages are steady on sole board with load, but drop out when the vga is connected surely that means the fault is on the vga board?

Can we have good pictures of the front and back of the vga board.

[Joun]

Re: LG L1953S doesn't power on

Yes but when I force backlight on (by applying 3.3V on inv pin) output on 12V drops to 10Volts..
I don't know what to think anymore, I have pictures of VGA board attached.Everything I could check on it is OK.Meaning I have check capacitors,transistors, 12V and 5Volt for shorts or low resistance etc.

[Dfrss]

Re: LG L1953S doesn't power on

Hi guys,
I'm new here, found this forum by googleing about my problem.
Its pretty much the same as mentioned on top, (LG flatron L1953S is dead) but I found dead component in my board, worst thing that it melt down so bad, I cannot read the model name. so I wonder can you tell me the model of (transistor I think) EL13 marked on board.
Thank you anyway
and greetings from Lithuania
Dfrss

[jetadm123]

Re: LG L1953S doesn't power on

Hi guys,
I'm new here, found this forum by googleing about my problem.
Its pretty much the same as mentioned on top, (LG flatron L1953S is dead) but I found dead component in my board, worst thing that it melt down so bad, I cannot read the model name. so I wonder can you tell me the model of (transistor I think) EL13 marked on board.
Thank you anyway
and greetings from Lithuania
Dfrss

I believe EL13 is a test point. Transistors are usually labeled with a "Q". If Q101 is next to EL13, then it's a Fairchild SSS7N60B mosfet transistor.

[Dfrss]

Re: LG L1953S doesn't power on

I believe EL13 is a test point. Transistors are usually labeled with a "Q". If Q101 is next to EL13, then it's a Fairchild SSS7N60B mosfet transistor.

thank you soo much

[Joun]

Re: LG L1953S doesn't power on

Just to complete this thread I have to say that it was a faulty power supply after all..
I have bought a new one and now it is working like new.
For $23.5 I paid for it I think it was a good deal..

[selldoor]

Re: LG L1953S doesn't power on

Thats great thanks for letting us know.
You can fix the old one now

[dave481985]

Re: LG L1953S doesn't power on

Just to complete this thread I have to say that it was a faulty power supply after all..
I have bought a new one and now it is working like new.
For $23.5 I paid for it I think it was a good deal..

i have the same problem. can you please tell me where did you buy it?

[Joun]

Re: LG L1953S doesn't power on

At ebay..But maybe you want to replace C205 and C206 first..

[dave481985]

Re: LG L1953S doesn't power on

since i do not have any experience would you mind telling me why those two in particular?

thnx

[Joun]

Re: LG L1953S doesn't power on

Because they were defective in mine..And you can see here:http://www.ebay.com/itm/LG-L1953-Mon...item2a28c39e40
which other caps are most likely to go down..