Lg w2284f

[Behemot]

This is one of those displays with 12V external brick. I first noticed waves runing on both display (in image) and O-scope even though caps seem fine in the brick so far - will try with ATX PSU I trust, the frequency seems to be somewhat suspiciously close to 50 Hz.

In the meantime, I got this display with problem that the backlight is turning off after some time. It was supposedly tested with ATX with the same results. There are two independent transformers in the inverter, their secondary windigs differ for 3,93 % (4,01 % according to Fluke), may that be the problem? Protection from driving IC turning it off when current difference increases after some time?

[selldoor]

Re: Lg w2284f

It is borderline > 3% is usual for 2 sec to black but what is "after some time?"
10 mins an hour a day three weeks?
Heat related? try hairdryer?
Power saving mode? sleep mode? on PC

[Behemot]

Re: Lg w2284f

I will test that, for now I only know what I've been told - after a while screen goes black, LED is still on.

[Behemot]

Re: Lg w2284f

Can still see the waves in image with ATX PSU, I think it may now be only related to the transformers. Caps inside have somewhat lower capacitance (probably due to it) but nothing drastic so I think they are not the cause. Will take O-scope screenshot just as I download that half-a-gig driver package

[Behemot]

Re: Lg w2284f

Here you go, it's even worse than first time…+12 V rail taken.

[Behemot]

Re: Lg w2284f

Those transformers are marked LE-CF22-0 080719B(or 8?)-KI, have found nothing about them at all.

[Behemot]

Re: Lg w2284f

Just got univerzal tester, it says it has inductance of 2,36 and 2,41 henry, resistance 923,6 and 959,5 ohm. I have already used the display on remains of different monitor where was bad CCFL and I did not manage to replace it.

So maybe for future LCD panel I get, but more like for education, I can now get some similar transformers when I know the inductance and replace them both, do you think it's worth it?