LG W2242S with burnt out inverter transformer

[selldoor]

Re: LG W2242S with burnt out inverter transformer

Hi - You have either missed measuring or missed posting the most important
7-8. In your picture the secondary windings are 1 to 2 and 7 to 8.
The others are primary windings and are not often at fault.
7 to 8 should be within 3% of 1 to 2 ie 1006 to 1068 ohms.
If not it is probably bust but always worth taking out and checking again.

[oldmanhouse]

Re: LG W2242S with burnt out inverter transformer

Thanks for the insight into how you solved your problem selldoor and thanks for the link - that's half the price of others I've seen on eBay.

I replaced all the electrolytic caps on my board with new Rubycon ones and it's made no difference. I've taken readings from the transformer (in circuit) but I'm not sure how to interpret them. They are as follows (multimeter set at 2000ohms):

1 & 2 - 1037
3 & 4 - 003
3 & 5 - ~005 (approx. as reading kept jumping about, and usually settled at a figure <10)
3 & 6 - < 010 (same as above. Reading was often different, but usually <10)
4 & 6 - < 010 (same again)
5 & 6 - 001

I took readings between each of the pins, but only the ones above gave a reading. I'm guessing this means something's popped inside?

I've attached pics for reference to show how my numbering convention correlates to each pin.

[selldoor]

Re: LG W2242S with burnt out inverter transformer

Hi - I did this some time ago with a w2042S replaced all the caps - made no difference. My transformer was an EEL22D******** and as I was not fully convinced from my testing ( difference was just about on the 3 % )that it was not the backlight bulbs didnt want to pay a lot for the a transformer. Left it for a while and eventually got one of these-http://www.ebay.co.uk/itm/Transformer-EEL-22-AIP0157-LG-L1719S-L1919S-/260738745349?pt=LH_DefaultDomain_0&hash=item3cb53d8405 which is a lot cheaper than others. It took the usual long wait from China but it works great.

[oldmanhouse]

Re: LG W2242S with burnt out inverter transformer

Thanks for the replies guys. I'll replace the caps as they're cheap, and will do some testing of the transformer itself

[jetadm123]

Re: LG W2242S with burnt out inverter transformer

Since you already removed the inverter transformer, check it for shorts. With your meter set to 2K ohm resistance, measure across each of the secondary windings. You should read no more than 3% difference between the two.

[Toasty]

Re: LG W2242S with burnt out inverter transformer

Discoloration can be simply from prolonged heat exposure of the board to the transformer. It does not necessarily mean the transformer is bad. Actually, the fact that it works at all sort of precludes a faulty trafo assumption.

The real culprit is likely those Su'scon caps.

Toast

[oldmanhouse]

Hi all

I picked up a cheap LG LCD monitor (model W2242S) on eBay and was hoping it'd be a simple job of replacing some obviously faulty capacitors, but I think there's a little more to it than that.

The screen powers on for a couple of seconds, displays the LG logo and then the display turns off. The power LED stays on. The classic "2 seconds to black", I believe.

The problem (or at least part of the problem) seems to be the inverter transformer as it looks like it's got very hot and left burn marks on the PCB. I'm no expert, so was hoping someone might know what could have caused this, so when I replace it, I can ensure it doesn't happen again.

Any help would be greatly appreciated. I've attached some pictures of the board, and a close up of some possible problem areas? You'll notice I've de-soldered the transformer (I wanted to take a look at it separately), but I can always take pictures of it if anyone needs them.

Many thanks,

oldmanhouse