Old LCD monitor = New lighting panel.

An LCD monitor with broken lines of pixels is pretty much junk as a monitor but taking one apart revealed an opportunity to make a cold light panel chucking out a good 100W equivalent of light. It took about half an hour.

WARNING
There is a possibility of serious electric shock with this little project if you are not careful. I should imagine that it pretty much negates any warranty as well. If you do not know what you are doing don't do it. (Thick rubber gloves and even Wellingtons throughout will help to prevent any possibility of electric shock.) 
An easy and very effective safety tool is to use a Earth leakage trip safety power socket. These are often supplied with electric lawn mowers or hedge trimmers.

Back to the project. The monitor in question was a 19 inch Ryoku job.

Picture courtesy of Google images

In case you don't know how these monitors work, the monitor is in layers with a cold cathode tube at the top and bottom.

These feed light into a perspex panel which has some rather natty sheets of plastic layered on. They vary from semi silvered layers to something that looks like a fresnel lens. Anyway, the net effect is to produce a homogeneous panel of light behind the actual LCD panels itself. 

The LCD panel uses a combination of polarising filters, colour filters and LCD cells to create pixels of varying colours by allowing the light through (or not). The LCD bit is all that is broken here.

Anyway, strip down the panel and inside you find (amongst other things) the black LCD panel which is the broken bit. 

There are also three circuit boards. The black LCD panel is attached to the largest of these. Disconnect all the wires and discard both the Black LCD panel and the circuit board it is attached to.

This panel circuit board and LCD are shown separately above. I have ripped off the ribbon cables attaching it to the monitor.
The other two boards are an i/o board which has the video sockets on it and the power supply / Cold Cathode supply board.

 

Here you can see the power wire from the 

PSU board to one of the Cold Cathodes.

Careful with the power supply, there are some high voltages around to supply the cold cathodes (as well as the mains of course).

At this stage, if you apply power and turn on, the panel lights up for about three seconds and discovering that no computer is attached, turns it off again. I nearly gave up at this point but careful examination of the boards revealed that one of the signal wires from i/o board to power supply board is labelled on/off. I pulled this off the plug at the i/o end and touched it to various pins on the i/o board. I found one pin that delivered the appropriate signal ( Vcc probably) that kept the panel on. I soldered the lead to this pin. This is illustrated below.

The PSU / Cold Cathode board showing the 
labelled signal lead from the i/o board. 

I disconnected the lead that was labelled on/off from the i/o board end. I then connected this to the pin on the i/o board that kept the lights on. I have attempted to illustrate this on the next picture.

At the end of the process you end up with a cold light panel.