Dell Ultrasharp Flat Panel, almost no image/brightness

[Kurtz]

I have a dell flat panel monitor lcd that has no brightness to the image. If i look at the monitor under a bright light i can faintly see the image.

Its not because the brightness is down, even in test mode you can barely see the "red/yellow/green/blue" message.

The model is 1504fp.

Ive opened it up but i cant go much further then that. Any ideas?

Thanks

[Guest]

Hi

I think you will find that the fault is with the inverter circiut that feeds the
cold cathod tubes (back lighting).

There are two high voltage transformers on the inverter board and if one
should go faulty, the board shuts down.

I'm in the midle of trying to source parts for one of these myself.

So cannot help any futher at the moment.

Best of luck
Ken

[JamesQB]

Hi,

As previously said, you will have a problem on the inverter board, responsible for stepping up 12VDC or so to several hundred to run the CCFL tubes.

I have had many different faults cause these boards to either stop working completely, or one side to have a fault which causes all sections to shut down.

First check the surface-mount fuse for O/C if present. Check that none of the HV transformers have burnt windings. Check the switching MOSFETs near the transformers for S/C. Check the ballast capacitors near the HV transformers (each is across a primary winding and often 100nF).

Nearly always the fuse. I have found suppliers for some of the parts needed on these boards, so if anyone is having trouble, just say what you're searching for and I'll see if I can help.

[Guest]