Flickery Backlights in LG L246WH

[canadaboy25]

Hello I have an LG Flatron L246WH Monitor that I got for free.

At first It had a bad fuse, MOSFET, and diode. I replaced all and then it was working fine. A while later I took it in a trip in our trailer. It must have gotten bumped on the ride because when we got there there were no backlights. The lights would sometimes come on when I bumped the backside of the monitor. Now they will not come on at all. All of the caps and diodes are fine. The problem is on the power supply board because when I test it there is no 12v or 24v going to the inverter board. The bridge rectifier is good and so are the MOSFETS. I have taken the transfomers off but I don't know how to test them. I have a digital multimeter.

Any guidance would be appreciated.

[1supertech]

Re: Flickery Backlights in LG L246WH

check this site http://preher-tech.com/documents/tes...ormersinlcdtvs
also check your CCFL bulbs one may be broken.

[canadaboy25]

Re: Flickery Backlights in LG L246WH

check this site http://preher-tech.com/documents/tes...ormersinlcdtvs
also check your CCFL bulbs one may be broken.

My ccfls and trasformers are fine. The power supply board and inverter board are two seperate ones. My power supply board is not outputting 12v or 24v to the inverter board. I took the transformers off of the power supply board and wanted to test them with a multimeter.

[budm]

Re: Flickery Backlights in LG L246WH

I doubt it very much that it is bad transformer, since you can bump it to make it come on before and now it is dead, I would inspect the solder joints closely. You should also check to see if you have 170vdc on the main cap right now.
Do you still have 5V? Pictures of the boards?

[canadaboy25]

Re: Flickery Backlights in LG L246WH

I re-soldered all of the through hole components and now it is working.

It must have been a craked solder joint.

[budm]

Re: Flickery Backlights in LG L246WH

Glad to hear it is working now.