LG L1953S doesn't power on

[jiroy]

Re: LG L1953S doesn't power on

With those screens , you better change badcaps first , even if not bulged ...

https://www.badcaps.net/forum/showpo...3&postcount=21

[Tomash]

Re: LG L1953S doesn't power on

I know it's an old thread, but I have several monitor with exact same problem.
To clear other funny readings in original post:
-12V output falls slowly - it's actually not powered (many caps on it)
-5V output falls faster
-U101 Pin 7 get's to 12V then crashes - probbably tries to start and bleeds out, this is repeater in about 1sec intervals
-U101 pin 1 should be line voltage, but falls a bit, due to resistor R108 and U101 initiative to charge C103 cap
-U101 ping 8 should get 5V reference voltage, but it also crashes, since U101 can't start in normal operation
Tempetarure has something to do with it. As I said, I have several monitor with exact same problem and when they are warm or have been recently in operation is fine. When I cool them or have been long unpluged, they won't start.
Help me please

[priitvillems]

Re: LG L1953S doesn't power on

Hello,
In my case problem was caps and the short-circuited U303 (4511GD).

[dave481985]

Re: LG L1953S doesn't power on

yup and they work great
i changed all 6 after all and it did the trick
thnx for ypur help

[Joun]

Re: LG L1953S doesn't power on

Are they 105 Celcius rated?

[dave481985]

Re: LG L1953S doesn't power on

thnx for your reply
i already bought these capacitors from a local shop for a lot less ans i am going to try to replace them
the top of c202 and c204 is a little bloated so i think i will start with them

[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..

[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

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

[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?

[selldoor]

Re: LG L1953S doesn't power on

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

[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..

[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

[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

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

[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.

[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

^^ 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..

[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?

[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.