Any Ideas? I have some experience with Tube type monitors / TV's but very little with LCd types. During the 1 second of display I can see my desktop and everything looks fine, Color, Size, position. It simply won't stay on for more than a second. I can turn it OFF / On and I get the 1 second burst of display then it goes black. ?? It runs on a 19 VDC external switchmode power supply similar to a laptop battery charger.

I also rebooted the pc to check if it works in the post screen (different mode) nope, same result, flashes on for 1 second then dark.

Look for threads of monitors with similar problems.
Quite recently our local god Richard B answered such a similar thread with these wise words (or similar) :
Most likely your lamps are gone, or the inverter to these lamps.

A defective lamp might very well destroy the inverter to it.
This defective inverter will then trip the protection circuit in the power supply.

I have just had a 17" with the same problems one lamp tired causing shutdown of inverter.

But the fault can be caused by 4 things

Lamps, tired lamp/s can cause this as the inverter monitors the lamp voltage if too high after say 1 to 2 seconds then it shuts down.

Inverter, open circuit capacitor or failing out put transformer.

Main PCB fault in the main PCB can turn off the enable inverter signal rare.

PSU, failed capacitors in the psu can cause this and other faults.

Rich B

I am not familiar with LCD monitors / theory of operation. Thanks for your suggestions but now I ask if you could give an explaination (or point to a webpage where I can read about it) of how these monitors actually work so I can better understand how to fix it.
Thanks in advance.

James

A normal CRT generates it's own light by shooting electrons at a fourescent surface, as you might know.

A LCD does not.
It consists of a few layers.
First layer is the light source.
Most often this consists of lamps similar to TL lamps but very much thinner.
Smaller displays have 2 lamps, larger more but that depends on the model of the display.
Future displays might have LEDs for this purpose. (nowadays the smaller displays have this already).
Then there is a diffusor.
As the name should tell you this should devide the light evenly across the surface.
Next there are colour filters R, G and B.
The the active part of the display follows.
Very short, this is a series of switches (much like a mirror) that switch the direction light will travel.
They either will let light through to the glass plate you are looking at, or not.
Every pixel has 3 of these switches, one per colour.
To ensure you will see only the light travelling directly to the glass, and not under some angle, the last (but one) layer is a polarizing filter.

This is a very simple description of such a display.
But it shows that when the lamps do not work, you will not see very much on the screen.
If you look really close however you will see your desktop.
Maybe you should use a flashlight to try this.

Thank you for an excellent quickie into the life and operation of LCD displays. Is that replaceable? Or is it junk?
Thanks again.