Rewiring an old Laptop Screen for PC use

[Breadfan]

I got myselt an old P1mmx IBM Thinkpad 760XL for 15 bucks yesterday. Its missing parts, and I'm doubting it'll power up.

But, I didn't buy it for a laptop. I'm pretty sure it'll have a nice active matrix screen, and it looks to have ither a 12.1 or 13.3 inch screen.

So I'd like to remove the screen (not the hard part) and rewire it to run off a standard computer (the hard part).

I've yet to remove it, but am sure I'll be met with some unmarked wiring. I need to find information on a few things:

1.) It'd be real nice to find a guide for this, i know others have done it...maybe not with an IBM though...

2.) Wiring specs for the screen. (I'm gonna check IBM's site later for a tech pdf or something...)

3.) Voltage requirements...i.e. with the power input, does it take 7v, 9v, 12v? I don't want to overpower it and blow something out!

So, any information anyone has to wiring a laptop screen for PC would be helpful reading!

Thanks a bunch!
Mike

[Captain Slug]

1.) It'd be real nice to find a guide for this, i know others have done it...maybe not with an IBM though...

A.) All the others you've seen are kits available at Earthlcd.com (http://www.earthlcd.com) (more on why below).

2.) Wiring specs for the screen. (I'm gonna check IBM's site later for a tech pdf or something...)

Here's a cross reference sheet (http://www.glorycomputers.com/lcdcrossweb.htm) that will give you the screen part # for your laptop. This will make finding the correct documentation alot easier.

Edit: Your Screen is IBM 760XL 12.1 TFT Screen Part #46H5725

3.) Voltage requirements...i.e. with the power input, does it take 7v, 9v, 12v? I don't want to overpower it and blow something out!

Since you bought the whole laptop you have the inverter for the screen which will supply the correct mA to the backlight. It needs to be fed 12V.

Explanation:
Unlike CRTs, LCD screens are fed a "clean" digital signal to display video. This means that the signal isn't being converted/resampled before it hits the screen itself.
However, current video cards convert their native image into an analog signal so that it can be displayed on a CRT.

This means that the process would go like this...

Video Card Output (converts Digital to Analog) - LCD Controller (converts Analog to Digital) - LCD Screen (receives Digital)

Option 1
SO, this difficulty in getting the signal in the correct format takes alot of complex hardware. This hardware is referred to as an LCD controller.
LCD Controllers are what make LCD monitors so expensive. The screens themselves are comparably inexpensive to produce, but they have to be supported by complex hardware.
This would be your most expensive option because LCD controllers START at $200.

Option 2
DVI connections were supposed to aleviate this problem but failed to deliver any significant price drops.
IF you have a DVI connection on your video card, your most inexpenisive option is to locate a DVI Receiver which can reformat the signal from the DVI on your video card, to the Dual TFT signal that your screen is using.
DVI receivers are $120-$150 on average.

That would simplify the process...

Video Card Output (Digital) - DVI Receiver(Splits Digital to correct channels) - LCD Screen (receives Digital)


Option 3
Apollo Displays (http://www.spollodisplays.com) has a line of AGP and PCI video cards that can connect DIRECTLY to the LCD screen without having any inbetween hardware. They cost $175 for a working sample that has to be order over the phone. All of the video cards are ATI Rage LT Pro based so don't expect to do complex 3D.

That would REALLY simplify the process...

Video Card Output ((Splits Digital to correct channels) - LCD Screen (receives Digital)

Option 4
Earthlcd.com (http://www.earthlcd.com) has a deal where you can trade in ANY LCD screen for a $50 rebate on their $299 12.1" XGA TFT screen kit.
Choosing this option would be the easiest out of the bunch because you'd be trading a screen that you can't be sure wether it will work of not, for one with a warrantee.
Your current screen may also have a maximum resolution of 800 x 600.


Granted there are more options available, but they're even harder to find and harder to get working correctly. If you have any more questions feel free to PM me because I've been researching how to hook-up my bare LCD screens for the past 6 months and haven't decided on which option to go with.

[Mpegger]

You forgot option 5. Take that sucker and make yourself a poor mans DIY big screen projector.:D

Seeing as how Even the cheapest projectors cost at least $1300, $15 for a good LCD panel and $200 for controller is cheap. All you need now is a method of enlarging the image. Plenty of school overhead projectors on eBay can be had for cheap. The only downside would be the price of lamps, which in the case of overhead projectors last around 75 hours and cost about $25 each.

But just think. DVD movie @ 8 feet x 6 feet. Gaming @ 800x600, again at 8 feet x 6 feet. Maybe even attach your home consoles to the whole setup.:D

[kd7aze]

Solution for making it bigger? Lenses.

Difficulty of making something like you say? Huge.

The biggest problem would be the backing on the LCD. It would have to be huge. Then there's the optics - possibly have to be custom ground for a projector.

An alternative - overhead projector. Already takes a large "image" (say 8.5 x 11) and projects it. You'd still have to work out the backing problem, but it would be more realistic a solution.

Still, this thread poses some really good questions. Now for another one. What would the Difficulty/possibility be of merging video card on Laptop to mobo video card.

Kid

[Captain Slug]

Originally posted by kd7aze
What would the Difficulty/possibility be of merging video card on Laptop to mobo video card.

Fat chance + When hell freezes over

hehehe j/k

Eventually the cost of doing that would reach the cost of simply BUYING a video card that can output directly to the LCD screen.

Originally posted by MPegger
Take that sucker and make yourself a poor mans DIY big screen projector

Not all that hard to do. You'd simply need to...

1. (HARD PART) getting the bare LCD screen to work with a regular PC.

2. Remove the backlight and metal sheeth from the LCD itself. The actual membrane is transparent and only gets it's light from the backlight, which is a flat cold cathode.
You'd end up with a projection screen AND a new cold cathode to play with :D

3. Find or purchase a working overhead projector.

4. place the "naked" LCD on-top of the projector, then mask out the areas it doesn't cover with some tape or something.

5. Focus the lens until the image isn't fuzzy.

Some companies made black and white LCD screens for this purpose. But they were then replaced by video projectors.

[h0mersimps0n]

wait, why couldn't he just use the controller the laptop was using to drive the LCD? Find the junction where the LCD controller attached to the laptop video out (inside somewhere) and solder a DVI end to the LCD controller to plug into some GF4 4xxx card???

[kevin_bouchard]

wait, why couldn't he just use the controller the laptop was using to drive the LCD? Find the junction where the LCD controller attached to the laptop video out (inside somewhere) and solder a DVI end to the LCD controller to plug into some GF4 4xxx card???
probably because its all intergrated into the motherboard like most laptops(to save space and costs) but there is always the odd exception, i guess there no harm in checking:D

[Breadfan]

Originally posted by h0mersimps0n
wait, why couldn't he just use the controller the laptop was using to drive the LCD? Find the junction where the LCD controller attached to the laptop video out (inside somewhere) and solder a DVI end to the LCD controller to plug into some GF4 4xxx card???

That was my next question...I was gonna open it up and check that out.

Its clear where the LCD goes into the board, but I've yet to remove the covers there. I'll have to try that later.

I'm giving it a 95% probability that the laptops lcd controller is part of the video. I dunno...we'll see.

Geez at this point I think I'll just get one of those $50 5.6" TFT LCD's with the RCA input...

I'll keep playing with the laptop LCD though...just right now I'm not betting I'll get it to work without putting a few hundred into it...

But...we'll see how it goes. Thanks for all the advice guys, I've got some work to do now :)

Mike

[Captain Slug]

Originally posted by h0mersimps0n
wait, why couldn't he just use the controller the laptop was using to drive the LCD? Find the junction where the LCD controller attached to the laptop video out (inside somewhere) and solder a DVI end to the LCD controller to plug into some GF4 4xxx card???

Most mobile graphics chipset were made for direct communication between the motherboard and the screen itself so there's no way to seperate it.

[kevin_bouchard]

Breadfan is Geez an online store, if so can you post a link, for 50$, I could get one of those 5.6" TFT LCD's and then make a amazing projector.:D Resolution would probably be crap but my eyes arent the same as before i came to the computer scene and the distance might help my sight. I would appreciate it so much. :cool:

[Captain Slug]

Originally posted by Breadfan
I'm not betting I'll get it to work without putting a few hundred into it...
You are soooo correct. I'm still waiting for the pieces I need to fall out of the sky ;)

[Breadfan]

Well I'm holding onto mine, still not sure what I'll do with it. Its a 12" TFT...maybe someday I'll look for the conrtollers for it...

As for the 5.6", heres a link to the thread in Cyber Deals:

Link Here (http://forum.oc-forums.com/vb/showthread.php?threadid=105860)

Mike

[kevin_bouchard]

thanks for the link, man i feel stupid for misreading your post and thinking Geez is an online store:p

[Zer0fight3r]

Another thing you need to consider.

Can it do 16Bit?

[Captain Slug]

Originally posted by Zer0fight3r
Another thing you need to consider.

Can it do 16Bit?

You can find out by crossreferencing the screen with the laptop that it came from by checking this rather complete list (http://www.glorycomputers.com/lcdcrossweb.htm).

Than, search for reviews of that laptop, ebay auctions with accurate information, or archive technical information from the company that made the laptop.

If that yields no results you can try finding documentation at the website of the original manufacturer of the SCREEN itself.

The information you find while looking this up will allow you to find a compatable LCD controller for your screen. Most companies that sell LCD controllers will be able to help you find a controller if you simply give them the information printed on the label located on the back panel of your bare LCD screen.

And in case you hadn't already guessed it, making your own LCD monitor is one freakin' huge HEADACHE!!!!

[SniperXX]

Originally posted by Captain Slug


And in case you hadn't already guessed it, making your own LCD monitor is one freakin' huge HEADACHE!!!!


You can saw that again. I was looking into using a laptop LCD too, but never wanted to shell out all the money. So I just didnt do it.

[Phugbox]

it would be cool to just get one of those 50$ 5.6 inch lcds and hook it up, but it would be nice to be able to hook up a laptop monitor instead. For a few reasons, Size, laptops generally have a screen size that is larger than 5.6 inches. And resolution, since those 50 buck ones are designed to replace televisions, which don't have the best res anyway. Of course, mind you qubbling about resolution at that size is useless.

my main beef with using one of those playstation dohickey's is that you probably get power for it from yet another cube, and I don't want to make a new addition to my cube farm. I'd be nice to have it all hooked up inside the case, feeding off your powersupply, build a switch into a panel and do it like that.

Would it be possible to feed that little sucker from your powersupply? I don't know, I know nothing which is why I read around here. of course, once I get that done, mounting that sucker in the front of an all plexi case, or in the side panel, or behind a window would be sweet. be bitc]-[in' for lan parties, useless for games, but still... bitc]-[in.

[Captain Slug]

The Gamevue draws power from the PSone connection which I'm 99.9% sure is also 12v.
Snip it and attach a molex connection and it should work fine without much hassle. LCDs have a very low current draw.

[Phugbox]

Nice, when I build that all plexi case, I think I will very much consider putting in on of those suckers. no need to lug your hefty crt arround hen all you need is to navigate your desktop. heck if you really ant to, no need to bring a monitor to a lan party, just sit there and stare at your case.