Can I turn my lcd laptop monitor into a desktop monitor?

After reading up a lot about this topic, i have concluded that this is pretty much impossible to do, considering the different voltages used by lcd screens on laptops and that used in common desktop lcds, a lot of other forums have also stated that this will not work, good luck to your 'gifted' son though

 

hey i have a NEC laptop monitor and i just took it out...are u sure there is no way that the conversion can be done? i read someplace u need like a controller or sumthing

 

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

[bold]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.[/bold]

The standard for this input for most LCD's is presently (of 2004/2005) - [bold]Low voltage differential signaling (LVDS)[/bold]. 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.

 

Very well said Johnathon!

That is partially why I said you need to know how to soilder. I have been playing with cut off the video controller from the mother board and solidering on the cable direct. This is very painful as boards seem to be changing.

Depending on the notebook, very few seem to isolate the video controller form the motherboard, most are now intergrated. Why I say this is the thing that used to run the LCD is the best thing to run it in the PC. But converting an old video board to fit a PCI slot is being more of an Engineeering Master's project. If your lucky and the video controler is isolated, then adapting it seems quite crazy. The easiest thing I can think of is buy or use and old PCI video card and solder in the conections of the old Notebook video controller to it. Then leting windows know what type of monitor you have seems like it might be later software fun, or I could be wrong and Generic LCD might work. I am still using a hack saw to cut the old mother board right now

So Yes I still think its possible. But No others should really try doing it. Because BenQ LCD's are now under $200!!!

 

how much would a controller cost me? i have a NEC NL10276BC26-09 ?

 

Prisoner my apologies, I had not thought properly about your comments earlier. You are right, if you want to hook one up to a desktop then the easiest way would be to mutilate an existing PCI video card and marry the laptops exiting FDPlink circuitry to the graphics adapter (sounds a lot easier than it would be). Personally I want to be able to use my old LCD's with my latest laptop and hence need to be able to plug it into a VGA port (wish it had a DVI-I/D port).

I have now found numerous discussion on the internet about this topic and here are lots of links to look at:

[bold]Controllers with Prices[/bold]
http://store.earthlcd.com/s.nl/c.318770/sc.7/category.5/.f

[bold]Discussions[/bold]
http://www.techwarelabs.com/community/viewtopic.php?t=1313&postdays=0&postorder=asc&start=0
(17 pages of discussion - the later pages interesting but no real "meat")
http://www.pcclub.com/forum/arcmessageview.cfm?catid=28&threadid=2611
(this guy bought the controllers etc from above link and has it working with images - cool but expensive!)
http://www.forumplanet.com/planethardware/topic.asp?fid=3710&tid=1467022
(Another discussion)
http://old.area26.no-ip.org/?section=hard&project=vgalcd
(This guy built his own circuit for a TFT screen and it kinda works - well done but old analogue TFT not same as modern digital LVDS LCD)

[bold]Education on TFT and LCD technology[/bold]
http://graphics.tomshardware.com/graphic/20041129/index.html
(highy recom. read the whole series of pages on DVI especially DVI connectors as has wiring pin-out)

[bold]Alternatives[/bold]
http://www.globalcomputer.com/applications/refurb/refurb_slc.asp?page=3&CatId=12&category=Monitors
(Just to keep things in perspectives - refurb. LCD monitors at rock bottom prices from trusted reseller Systemax)

My current thoughts are this, LCD Monitors are different from LCD Displays in Laptops in one big way. Laptops don't contain the TMDS circuits (Tx/Rx - refer to http://graphics.tomshardware.com/graphic/20041129/tft_connection-02.html for more info).
This is probably because everything is nicely contained in a small package and the cables/data do not need to traverse any sort of distance like it would for an external monitor. Hence the GPU output does not need to be converted to a serial data stream from being parallel and back again (for RFI/EMI reasons).
This is a good thing as it supports Prisoners suggestions although a a power source/supply for the inverter would need to be arranged (+12 volts with approx min. 1.0amps - I'm guessing) but the PCI card should be able to supply the 3.3volts to the FPDlink circuits.

Of course in my particular, case none of this really helps as I need a USB 2.0 adapter with a DVI output (I have found the [bold]Sitecom.com - CN-105 - USB 2.0 to VGA adapter [/bold] but it is VGA/analog). If I could find one of these then I could "marry" old LCD controller (FPDlink circuitry) I pulled ouy with the old LCD screen.

Whatever the outcome this investigation has so far been very educational.

 

so i think i understand the incompatibilities between vga and dvi. I recently have had an old lcd that i was going to use as a monitor. I had all but given up on it until i found a 3d card that supports dvi. Its a geforce 5200 i think, 128 mb 8x with dvi ( 30 pin connector). Laptop lcds are 20 pins which got me stumped. is there a way i could convert a 20 pin to 30 pin? Heres a link to laptop lcd pinouts http://www.pinouts.ru/data/dfp_pinout.shtml
is there still a possibility i could get this to work? i want to build a projector using the lcd, and im hoping this works

 

flipf0nt, I think you miss understand. The more I read about this I don't think you can take the cord from the LCD and add a 30pin plug to it. The LCD needs a bunch of stuff that the computer used to give it and the normal LCD screens have.

 

flipf0nt,

Prisoner is right. It's just not that simple. The here is flow of connections I imagine any PC/External Monitor combination would require.

I know this is really hard to follow but its difficult to type concise relationhips using this interace.

[bold]CPU ... Graphics Card/Chip ... Graphics Transmit Interface (DVI or VGA)

<< CABLE either VGA OR DVI>>

... Graphics Receive Interface (DVI or VGA) ... LCD Controller

<<LVDS CABLE to LCD.

<<CABLE to INVERTOR>>

... LCD Inverter <<< SWITCHES FOR POWER AND BRIGHTNESS ETC TO INVERTOR (OR VIA LCD CONTROLLER IN MOST CASES ON TYPICAL LAPTOP)
[/bold]
Basically what you are missing in your case is the LCD controller which converts the signal from DVI (which is a particular type of interface) to LVDS which is the type of signal most LCD's are expecting.

Please also note that the DVI cable is not providing misc. necessicary functions such as an ON/OFF switch and brightness etc. At least it is not as far as I know. My understanding is that this is always part of the unique and specialised circuits within a laptop or monitor and specific to how the manufacturer wants to implement them - i.e. hardware or software etc.

Hope this helps.

Johnathon

 

I have an old lcd screen from a toshiba portege 3010t and i was wondering if it is possible to make it work with a standard monitor cable?

 

no you would need a controller board.

 

Which board would i need

 

well i had a similar idea but the problem was the more popular companies only make controllers for big lcd's so you could first call up the company that makes your lcd and ask them for compatible controllers and if the dont give you any answers (they most likely wont) you ask them to email you the manual to your lcd. When you know all of the exact specs you can begin your search on what u need. Dont forget that LCD's dont run on a DC current, they need AC so if your controller bord doesnt have one you might need to get an inverter. You should contact someone that may know about your monitor like the guyz at EarthLCD.com they know exactly what you need.

 

My video card has a port to use an lcd monitor is it possible to wire that to the laptop lcd?

 

hmmmm i havent heard of that and if it is true it wouldnt make any sense because the vidio card is analog and the lcd is a all digital signal...do you have any pics?

 

Hiya.

Would having a graphics card with a DFP connector make you not need the LCD controller ?

 

OK guys here it is, THE GUIDE ON HOW TO CONVERT A LAPTOP LCD INTO A REGULAR COMPUTER MONITOR. I'm a physics grad student and I have been working on this for a few weeks now. Here's what I've learned. In newer TFT LCDs (the only ones worth your time), a new standard known as FPD-link is used. Basically, this bottles all the video info down into 8 wires using a form of low-voltage differential signaling (LVDS). Those 8 wires are all it takes to run an LCD.

First off, there isn't a "twisting wires together" way of doing this, but there are some myths. I keep hearing people say, "you need a driver", or "you need a controller", well they are full of it. The driver chip is built into a small circuit board on the LCD itself, so you already have it. And you don't need to spend $200 on some PCI video card with 2 MB of video memory to drive your LCD. All you need to do to make an LCD work as a desktop monitor is feed the proper signal into the driver chip you already have. Normally the LVDS receiver does this, but you don't wanna mess with LVDS, in fact I wouldn't have a clue how to multiplex the signal into FPD-link format aside from using a LVDS transmitter.

So, the way to do this is (theoretically, I haven't done it yet) to de-solder the FPD-link reciever chip, and solder your inputs where its outputs would have been. As for the video, it will sound difficult, but its actually easy. You need to make a few seven (or maybe eight in some cases) bit Analog to Digital Converters (or ADCs, note: my Hitach screen from a Dell Inspiron 7000 uses 7 bits for each color). You will need an ADC for each color (3 total). Then you just need to figure out which clock speed your driver chip needs (I believe this is called the dot-clock, and I think its usually 85 MHz) and set your ADC sample frequencies accordingly. (In my case the sample frequncy should be a "divide by 8" (industry term) since there is seven bits and a "dead time" where no data is read), Oh, and you will need a phase-locked loop (PLL) at the proper frequency to generate the master clock pulse for your converter.

If you guys want a schematic do me a favor and find me the datasheet on my LCD driver chip. I don't even know who makes it. its an 80-pin square probably LFQP, and labled as follows....

Tcon-16.1-F
SLA4028F2C
V99100289
JAPAN

Here's the deal, If I can ever get the datasheet that gives me the timing diagram for this driver chip (many other driver chips must be compatable as there are only a handfull of LVDS chips used), I can make the converter. I'll etch my own Printed Circuit Board (PCB) and solder up the everything (which will most likely be surface mount ). If it works, I'll post a tutorial, and most likely sell a few converter boards to the brave ones (don't worry, I'm not out to become a millionare from this). But my ultimate goal is to incorporate some extra video processing and get S-video hooked up (although component-input may be easier, I don't know). This would basically turn a laptop LCD into both a computer monitor AND a TV. In the final stages I plan on redoing the electronics to split the video onto four LCDs, making one big TV I can hang on the wall (with a small line down the middle of course).\

And I should be able to incorporate an LVDS transmitter chip on the board (eventually) which would mean: no removing chips, and just 8 wires to connect. These are the ones I'll end up selling

Anyways don't let people tell you it can't be done. I'm gonna do this for under $30, just watch. I'll post the schematic and pictures (of the LCD working, and the wiring) once its done.

Email Dneuf2@hotmail.com if you have the crucial datasheet or have questions. I don't mind answering questions, but please see if google has your answers before you ask me.

 

Cool!!!!

I can't wait to see if you get it working. I have been on hold with my project. As my actual research and work gets in the way of this fun. The aproach sounds logical, So I think it might work. Good luck.

By the way posting you e-mail address in full is a really bad idea. If you do want to post it use some random keyboard keys and tell people which to avoid. Spy ware on the net will send you e-mails like crazy soon.

 

Thanks for the tip, but my hotmail account is just for the purposes of stuff which could potentially result in spam, so it is flooded with it anyway. I still scan the titles of messages that make it through all my filters, and I have two other addresses which I use for communication. And by the way, I found that national semiconductor makes an LVDS transmitter that I think is compatable, so I'm gonna try to incorporate it into my first board (that way the LCD remains intact, so I can Ebay it if all else fails). I just need to figure out how to sync the dot clock with the Hsync pulse (non-existent datasheets are not helping) and this job will be done. Just out of curiosity, anyone know where I can find a datasheet on a Hitachi TX38D73VC1CAC (the last C just means its the third batch, so any letter here is acceptable) Hitachi isn't very good at returning emails.

 

I got money on a board if you can make this work!!!

something about a laptop lcd popping out of my dash makes me drool,
especially if I get to m0d something, and Im only using crap parts.

please PM me if you get this working!!!