LG W2242S with burnt out inverter transformer

[StevieBoy1912]

Re: LG W2242S with burnt out inverter transformer

Hi sorry for the unreliable data am new to this and I still have a lot to learn as you can tell when I tested the rectifier diodes I had the power supply plugged into the board, so there was power running through the board but I couldn't fully power the board on as it was unresponsive is that still bad to do with the meter or is it just as long as the board isn't fully powered on, I changed the LAF0001 chip and now the monitor seems to be working fine at the moment but it hasn't been on that long so fingers crossed.

[budm]

Re: LG W2242S with burnt out inverter transformer

"and the 450v cap when the board is on dose not hold more than 100V" Where did you put your meter probes?

[budm]

Re: LG W2242S with burnt out inverter transformer

You should never measure resistance with power on. It can damage your meter.

+1. I think he needs to learn how to properly use the meter first, otherwise we are doing the goose chase with the wrong data.

[jetadm123]

Re: LG W2242S with burnt out inverter transformer

You should never measure resistance with power on. It can damage your meter.

[StevieBoy1912]

Re: LG W2242S with burnt out inverter transformer

rectifier diodes are bouncing around from .1 to .5 Ohms when power is on I have no standby light, and the 450v cap when the board is on dose not hold more than 100v

[budm]

Re: LG W2242S with burnt out inverter transformer

hi I tested the rectifier diodes again to double check they are bouncing around from .1 to .5

Those numbers do not mean anything to me. Is it in Ohms, Volt, Amp. etc?
Measured with power still applied to the board? Measured with the components still connected to the board or out off the board?

[StevieBoy1912]

Re: LG W2242S with burnt out inverter transformer

I was thinking the other transformer because a few weeks before it died it was making a hissing sound then the clicking started and then one day the picture just slowly faded and the monitor just died I will check the power MOSFETS now is there any thing else you would recommend checking and thanks for the help.

Steve

[StevieBoy1912]

Re: LG W2242S with burnt out inverter transformer

hi I tested the rectifier diodes again to double check they are bouncing around from .1 to .5

[budm]

Re: LG W2242S with burnt out inverter transformer

I doubt that the SMPS transformer is bad, it is making clicking sound can be due to the fact that the circuit is in starup/shutdown cycle because it detects over current draw by the load. You have to use the same matching spec transformer.
Did you check the rectifier diodes, the power MOSFETS that drive the inverter transformer, etc?

[StevieBoy1912]

Re: LG W2242S with burnt out inverter transformer

Hi I have a lg w2242s and of course it's dead I have replaced all the caps with panasonic ones and the 470v at 100uf with a rubycon one and replaced the EEL22D transformer with the one from the link on this post but still nothing but my smps transformer in making a very loud clicking sound, the monitor powers on but not fully I was wondering if a smps transformer from a lg W1943SB would work or if anyone knows were I could get a replacement thanks.

Steve

[lozzbo]

Re: LG W2242S with burnt out inverter transformer

Hi,

Thank you so much for the excellent feedback.

Im going to order the transformer from the link right now!

Cheers.

[Rtech]

Re: LG W2242S with burnt out inverter transformer

"My question is:
Other than the transformer in the Ebay link, will I also need to buy some sort of inverter circuit board, or is this part of the transformer purchase?"
Don't get confused,the board that the transformer is on is a Power Supply AND inverter Board combined.

[selldoor]

Re: LG W2242S with burnt out inverter transformer

Hi If you have tested everything else and determined the fault is definitely
the transformer then that is all you need plus some soldering equipment.
Most members would recommend upgrading the caps on the power supply and the inverter board to prolong the life of the monitor.
Read this if you have not start at post19
https://www.badcaps.net/forum/showthread.php?t=10419

[lozzbo]

Re: LG W2242S with burnt out inverter transformer

Hi All,
I cant even call myself a newbie as I am completely ignorant of the technicalities involved.

I have a faulty LG2242S in a workshop at the moment and have been quoted £90 for the repair! During online research, I came across this haven of priceless information that may well save me a fair bit of money! The monitor normally lives in a recording studio, so any money saved on computer equipment would be spent in an area more specific to music technology.

My question is:
Other than the transformer in the Ebay link, will I also need to buy some sort of inverter circuit board, or is this part of the transformer purchase?

Sorry for my technical ignorance!

Cheers.

[selldoor]

Re: LG W2242S with burnt out inverter transformer

Well Done! Not too long from china - great to hear it went well.

[oldmanhouse]

Re: LG W2242S with burnt out inverter transformer

Update: bought a new transformer (one selldoor linked to), which arrived the other day. Fitted it and monitor is back up and running!

Many thanks to all for the help

[budm]

Re: LG W2242S with burnt out inverter transformer

I use thin stainless steel blade such as Exacto knife since the solder will not stick to it, to lift the pin up slightly when you slide it under the pin, main key is to take you time doing it.

[oldmanhouse]

Re: LG W2242S with burnt out inverter transformer

Excellent advice, thanks very much. I'll give it a go in the week when I've some time to dedicate to it.

[selldoor]

Re: LG W2242S with burnt out inverter transformer

Very Nearly,
It is worth taking it out and re-checking it. Just before you do that, I dont know where you were measuring but there is sometimes some lacquer or burnt flux on these pins so
try again (just for 7 to 8) making sure you have a good connection. Any I have come across have always had some ohms but if it has zero it may be worth getting a magnifying glass and checking the very very thin wire has not snapped off the pin - if it has it can be reconnected.

This means you have to be careful removing, which you have to be anyway:
Removing this is not easy, as at first none of it will want to move. You have to be careful not to bend the board too much especially as in this case the three ceramic caps 318-320 are very close to pins 3 and 5. Ceramics are quite brittle and do not like being bent.

As I recall I heated the transformer with a hairdrier and the underside of the board in that area just to stop the heat leaching away.

I then removed as much solder as I could from the pins using solder mop. I then started on most accessible pin and put a tiny watchmakers screwdriver in the gap between the board and the transformer then as I heated the pin pushed it in a bit lifting the transformer 0.5mm off the board. I then moved on to the next pin and repeated the procedure. Work around all the pins then with a thicker wedge go round again
Once you have a bit of a gap if you can move the pin slightly as it cools you can break the solder joint if lucky.

Give plenty of time its not a quick job - might want to tackle it in sessions.

[oldmanhouse]

Re: LG W2242S with burnt out inverter transformer

Ah I see, thanks for clearing that up. I wasn't sure which were the secondary and which were the primary, so I just measured them all.

I did take a reading for 7 - 8, but it's giving me nothing just like all the others not mentioned in my list above. Time to buy a new one?