LG 22EN43T not start

[Maxmad]

This monitor had problems turning on from time to time. Pressing on-off button made power led to blink with no picture.

After some tries ,once it started, there was no problem. Working perfectly.

Now, there is no way to turn it on after several tries.

The whole board is an eax65118801. I attach the schematic.

All voltages are fine , 5VS from IC102 and both 3.3VS and 1.2VS from IC103 are OK.
There is no voltage drop except from 0.5V on R100 when on-off button is pressed.

I checked 2 big SMD electrolytic caps, and some other ceramic.
Why not starting?? Do you think is a firmware issue?

[R_J]

Re: LG 22EN43T not start

I see this is NOT the picture of YOUR BOARD (C154 does'nt look good, it seems slightly bulged).
Post pictures of YOUR board.

If this cap on your board is bad the backlight will not come on all the time.
Have you checked the screen with an external light (flashlight) to see if there is an image on the screen? It could be the monitor is working and just the backlight is not working.

[Maxmad]

Re: LG 22EN43T not start

I upload a picture of my board.

C154 was checked, both capacitance and ESR are good.

This in not a backlight issue. There is no picture at all.
Monitor's power led is blinking. When was working the led was light steady.

Seems that the monitor "is not starting".

[frica]

Re: LG 22EN43T not start

Hello Maxmad:

I am not an expert but I read a repair of a monitor where the Power Led blinks and no turn on the monitor:

http://www.electronicsrepairfaq.com/...l-senso-m2289c

The expert repairer say "The stand by on this computer monitor was flicking which gave me the indication of a power supply failure. I was expecting either cold soldering joints, bad capacitors or could be both because I have seen it many times in my field of work"

The monitor was repaired removing and replacing same bulgy electrolitic capacitors. If in your monitor there is no capacitor problema, maybe the problem is cold soldering joints.

[Maxmad]

Re: LG 22EN43T not start

Thanks for your replay frica.

Unfortunately this is not a bulgy capacitor problem.

Maybe this has to do with cold soldering.


Today after keep pressing the power button the monitor powered on. Once it starts it's ok.


I am trying to find the start up procedure in order to isolate the problem.

[R_J]

Re: LG 22EN43T not start

At this point I would try a different power adaptor, It could be that the adaptor has an issue IE bad output cap. and the voltage to the monitor drops for a second causing the monitor not to come on. After a few tries the power supplies output cap is charged enough to keep the monitor on.
You could try adding a 1000µf 25v capacitor across the 19v dc input and see if this makes a difference.

[Maxmad]

Re: LG 22EN43T not start

Good suggestion, but no result.
I add a capacitor and makes no difference...

[R_J]

Re: LG 22EN43T not start

Check the voltage on P102, pins 1,2,5 & 6. Monitor pin1 when you turn on the monitor, then try again with pin2 and so on. It could be that there is a faulty led causing the problem.

[Dumah Brazorf]

Re: LG 22EN43T not start

I quote the suggestion to try another power supply.
Crack it open, bulged caps should be there.