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blimkie.k
Aug27-08, 09:33 AM
So I have an LCD from a laptop, I had another thread going where I was trying to fix this laptop. I learned a but from the experience but no luck, motherboard is toast.

I was doing some reading and there has been some succesful attempts to recycle the LCD and have it run from another computer. Now before anyone clever is quick to shoot my down, I know about how difficult and costy it could possibly be, but still id like to try. Ive done some googling and havent found anything quite useful.

My original thought when I had this LCD isolated from the laptop is that it would took really cool on some sort of stand by its self or just mounted on a wall.

As far as I know i would need to create a power supply for it and way to transfer the video single. So sometype of VGA to the input in the LCD onverter or connect it somehow to a desktop graphics card. Since desktop monitors usually get there power externally creating a power supply might be a problem unless i could figure out the specific voltage and amperage of the LCD then go about ordering one or making one I have alot of old parts.

Does anyone know a useful place to start reading about this or a place hwere i could maybe even find parts. What I belive to be the most complicated part will be determining which type of signal each very small wire off of the LCD carries. Ie some must be power some must be video signal etc.

Thanks.

PS has anyone else tryed this and can talk about there experience success or failures.

MATLABdude
Aug27-08, 02:14 PM
I Googled Laptop LCD Pinout (the usual starting point when you're trying to reverse-engineer something: see if someone's already done it!) and from the second result:
http://forums.afterdawn.com/thread_view.cfm/98801

There are a few points that need to be noted before everyone gets too excited.

The first thing to note is that VGA is an analogue display technology. Secondly, laptop LCD's are 100% digital. There is no correlation between VGA and LCD they are two totally different beasts and LCD's will only accept a correct digital input.

The standard for this input for most LCD's is presently (of 2004/2005) - Low voltage differential signaling (LVDS). In fact that thin "paper ribbon cable" on the back of your LCD is referred to as a LVDS cable. To read up on LVDS go here http://www.atip.org/fpd/src/rep/dism/dism.html section 4.2.

The other cable going into the back of your old laptop LCD is the backlight power. The makeup of this cable varies between model but the norm is roughly that this cable is fed from an LCD inverter. In other words the LCD backlight normally takes power in the form of AC rather than DC and it normally needs lots of it. Input power to the inverter is normally in the range of 5v - 12v. What you need to do is find the (EXACT) model number of your LCD on the back of it then go searching Google for specifications. Once you have that you can go here http://www.digitalview.com/support/controller-solutions.php and they sell a VGA input board hopefully suitable for your LCD screen. As far as I am tell Digital View don't sell direct so you will need to find a local distributor willing to order the board in.

Of course if you are going to go to the trouble of getting a LCD controller and power supply etc. it would probably be cheaper to buy a used external LCD monitor on Ebay (although not as cool).

The only other option I have discovered is a board called "Margi Display-to-Go PC CardBus 4MB Video Output VGA/DVI" which has since been discontinued. The cool thing about this board is that it had a DFP cable output which meant theoretically that could wire it into the existing LCD controller board from your old laptop and it "may" work. I have not been able to find any of these new or used on Ebay or elsewhere on the Internet.

So in summary, it would seem that it is cheaper (and faster/easier/practical etc.) to go and buy a new (albeit budget) LCD monitor than to retrofit an LCD panel you have pulled from an old laptop. This is quite annoying especially for me as I have quite a few old laptop lying around the house and it would be way cool to reuse them but having to spend £200/USD$350 for a controller and adapters does not make sense.


The first result links to a (more recent) board where people have managed to actually do this (but no, it's neither trivial nor cheap):
http://www.ocforums.com/archive/index.php/t-181128.html