LG W2243T-PF buzzes and shuts down a few times, then goes black

[camper]

Hi,

This LG W2243T-P has about 4 years now. The 1st signs of failing were a minor buzz and a top screen flicker in intensity. The following day these two got stronger and after 2-3 oscillation of buzzing and flickering it went off completely and still does that every time I turn it off and back on again.

Before I found some similar issues on this forum I've removed the SPW-102 transformer that's sitting next to the board in the picture. I've done this because it seems it's the buzz source and while nudging it while buzzing modified the sound that it made.

Can anyone please advise where I should start looking?
Let me know if I can provide more information and thank you in advance.

[selldoor]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

It may have been buzzing as a symptom rather than a cause.
It looks like all the high voltage solder joints between the ends of the transformer and the bulb sockets need reflowing some on the blue caps look a bit off , but may be the picture.

Tested the Transformer?

Problem may be bulbs or the wires to them - have you any spares - old laptop
screen or another monitor you are prepared to open up

[R_J]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Resolder the connections circled in red and any others that look like they are bad.

[camper]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

On the picture some connections are quite different than in reality.
I've resolder some as you can see in the new picture.

In the meantime I decided to check the lamps, I've disassembled everything and connected the lamps. I even moved the wires a bit to see if it affects something. They seem fine.

After that I've connected just the top or the bottom lamp alone.
When just the top one is connected it makes the buzz 2 times and shuts down.
When just the bottom lamp is connect it makes a barley noticeable high pitch noise and it goes off the same way after lighting up 2 times.

From my point of view there's something wrong with the power circuit for both lamps. I'm gonna buy a multimeter this Monday to check the spw-102 transformer and the capacitors along it's circuit.

Please let me know if you have more ideas or see something in the new picture.

Thank you.

[mscserbia]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Take a picture of that small driver board.

[selldoor]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Ok - perhaps clean the flux off the joints with IPA and an old toothbrush.

Testing one lamp or two at a time shows the bulbs are not totally broken but
you HAVE to have all for for them to stay lit. One could still be causing the shut down. I you have a 14w or less cfl lamp you can make tester bulb



As above - picture of the riser board and if you cant read the part numbers
on the components on the picture please list them.

[lexwalker]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

This LG W2243T-P has about 4 years now. The 1st signs of failing were a minor buzz and a top screen flicker in intensity. The following day these two got stronger and after 2-3 oscillation of buzzing and flickering it went off completely and still does that every time I turn it off and back on again.

Before I found some similar issues on this forum I've removed the SPW-102 transformer that's sitting next to the board in the picture. I've done this because it seems it's the buzz source and while nudging it while buzzing modified the sound that it made.

Can anyone please advise where I should start looking?
Let me know if I can provide more information and thank you in advance.

That board looks very similar to some of the boards found on BenQ monitors. Were those capacitors (with brown colored sleeve) near the inverter section Jamicon brand?

[camper]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

mscserbia: I've added a picture of the other board.

selldoor: Testing one lamp at a time buzzed just on one circuit (not the lamp), the top lamp circuit, and it wen on just fine.

lexwalker: Yes, the capacitors are Jamicon.

In the meantime I did not keep my promise to get a multimeter since most of them have the max measure capacity of 200uF and all the big ones from the board are way over.

But I've replaced the 6 ones since they are dirt cheap. Nothing changed.

I have not found a replacement in stock for the big one 150uF @450V. There was one @400V that I did not want since I didn't measure it's live working voltage and its the first filtering capacitor. It should't affect just one of the two circuits after the spw-102 transformer.

[selldoor]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

I've added a picture of the other board.

Not that board the small one at right angles to the power supply next to the inverter transformer

selldoor: Testing one lamp at a time buzzed just on one circuit (not the lamp), the top lamp circuit, and it went on just fine.


Are you saying it stayed on for more than 2 seconds??!



lexwalker: Yes, the capacitors are Jamicon.

In the meantime I did not keep my promise to get a multimeter since most of them have the max measure capacity of 200uF and all the big ones from the board are way over.

We cant do this without some sort of digital multimeter meter just to measure volts and ohms

But I've replaced the 6 ones since they are dirt cheap. Nothing changed.

They NEED to be low esr caps good make
Usually dirt cheap caps will be no better than those you took out.

I have not found a replacement in stock for the big one 150uF @450V. There was one @400V that I did not want since I didn't measure it's live working voltage and its the first filtering capacitor. It should't affect just one of the two circuits after the spw-102 transformer.

BIG cap is usually ok unless you can see signs of bulging/leaking

[camper]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Sorry about that, here's the requested picture.

[Teodule]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Hi guys,
I know this thread is old, but I give it a try anyway. Did you solve your problem? I have about the same issue with a very similar monitor (change the T to a S in the model number). I guess the transformer is dead: I measure 0 ohms for the primary windings. It seems a bit low to me, isn't it?

[camper]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Hi,

I did change the transformer and it behaved the same.
I gave up repairing it myself and went to a repair service. The top lamp was almost dead and I presume it made the transformer noisy.

They said a replacement from china would take 1-2 moths and offered to install a led back panel or something like that, for faster and for less money. It works great ever since.

[Andrew F. Ali]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

It would also use less power. Converting to LED was the best solution. I actually recommend and do the conversion for clients with CCFL or Inverter problems.

[Teodule]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

I am afraid I don't understand. What do you mean by "converting"? Is it obvious to retrofit an old CCFL monitor with an LED backlight? I know nearly everything is possible but that would be expensive.....

[Andrew F. Ali]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Converting a CCFL backlight screen to a LED backlight screen, is easy but sounds difficult, would entail removing the CCFLs and removing the Inverter or disabling (if PSU is IPS) and using the same signals required by the Inverter to enable a LED Driver to supply two (2)-6 LED strips.

[Teodule]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Well, yes it is indeed possible. However, it would require a nearly hand-made replacement. For instance the replacement would have to fit mechanically, optically and electrically. I have a couple of LED backlight systems taken from TV or monitor sets and none would fit my LG 2243.

[Andrew F. Ali]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

I have actually done several with none of the issues you are imagining. I get my strips and Drivers from a store off e-bay (US) and NEVER had any issue of fit and whatever else. The Driver is 4cmX3cm and the strips for any size screen will fit. You can't take a PSU/Driver Bd from a TV and try to fit it in in another that is absurd. The LEDs perhaps but not the PSU/Driver.

[Teodule]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Thank you for the hints. Next time I get a monitor with a broken inverter or CCFL I'll to to replace the lamps with LEDs.

[Andrew F. Ali]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

Remember though that you would have to get a LED Driver suitable to purpose and disable the Inverter. The 24V or 13V as B+, PWM signal, BL-ON/OFF signal and GND are the only things you would use in the conversion. Perhaps when you are ready to attempt this exercise you could post on the Forum and I'll give you a step by step detailed procedure but you would need to give me some information about the Monitor/TV. No problem I will be very happy to share with you this knowledge. Good luck in the future.

[Teodule]

Re: LG W2243T-PF buzzes and shuts down a few times, then goes black

For the sake of completion, I investigated why 1/6 of the LCD panel wasn't addressed vertically. Therefore I accessed the LCD panel itself with the bonded panel driver board. This board has 6 ribbon connections to the LCD panel. On each of these ribbon connections there is a tiny piece of silicon (demux IC?). For the defective part of the panel this tiny circuit was broken in the middle and getting very hot. Thus no regrets the monitor is returning where it came from years ago: the local dump.