LG Flatron W2246PM-BF 2 seconds fade to black

[Kentone]

Hello, I have an LG Flatron W2246PM-BF Monitor that fades to black after 2 seconds. I did review many of the threads here on the forum (RetiredCaps) and did replace the caps on the board for starters. After swapping out the caps I noticed the screen fade to black after 3 seconds and then would come back as the screen changed in the background for another 3 seconds and then fade to black again.

The caps I replaced were 2xNXB-1000uF 25V and 2xSuscon-1000uf 16v and they were replaced by similar Rubycon and Vishay caps. I then looked up the spec's for the original caps and diff'd them with the new ones and noticed the spec's were not exactly the same. The resistance for both were higher than the original.

Also I went to go one step further to find out if the transistor and transformers were bad. However, I seem to be having an issue locating the proper components as that the readings I was getting on my DMM was no where near what I was expecting which left me to conclude that I must be reading across the wrong components. I find one transistor that I tested and I get "open" on all three legs with the DMM. I've attached the photo's of the board, both sides and the caps I replaced.

Can someone point out the transformer and transistors I should be testing? Is there anything else I can check for?

Thx
KenTone

[Kentone]

Re: LG Flatron W2246PM-BF 2 seconds fade to black

ok, I'm guessing I'm missing additional details.

The capacitors I've swapped out were 2 x NXB 1000uF 25v 105°C and they were replaced by 2x Wurth 1000uF 25V Aluminum Capacitors Radial, Can 6000 Hrs @ 105°C

I also swapped out 2 x Suscon 1000uF16v 105°C capacitors and replaced them with 2 x Wurth 1000uF 16V Aluminum Capacitors Radial, Can 6000 Hrs @ 105°C

The only difference I later found out was the original caps were of lower impedance compared to the new ones.

Still with the newer caps I see the same 2 seconds fade to black issue.

Could the problem not be the caps?

[jondoe]

Re: LG Flatron W2246PM-BF 2 seconds fade to black

Have you taken any voltage readings from the board? Like at P201? U302 looks like it might be marked, does it have a burn on it? Or is that fluff/muck.

Edit: I looked up U302, I'm fairly sure it's a MOSFET, so well worth investigating. It probably has a similar pin out to this

[Kentone]

Re: LG Flatron W2246PM-BF 2 seconds fade to black

Hi Jondoe,

I did look at U302 and it's not burnt. I took off most of the smudge. It looks like some type of paint. I cannot locate the P201 component you mention. Could you be referring to PC201?

I have not taken any voltage's at this point. I tried to test for continuity as was instructed in one of the stickies here on the forum and got no where near the expected results which lead me to believe that I may have been doing it wrong.

Forgive me for this questions as that I am a newbie but to test for voltages on this board will it be necessary for me to reconnect everything back up or can I just connect the power to the board? (I'm thinking the former as that one of the connections is the power switch)

[jondoe]

Re: LG Flatron W2246PM-BF 2 seconds fade to black

I was referring to the bottom left white sockets on the second picture, those headers are marked with voltages and grounds, it's worth seeing if the those are at the stated voltages. You'll need to power it up, so take suitable precautions and don't do it if you're not confident!

Don't worry, I'm a newbie too