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31 March 2008 @ 01:21 pm
Hardcore laptop resurrection  
I recently came across a laptop with a smashed screen, dead battery, and no power supply. Here's how I made it into a franken-laptop.

The laptop
This Lenovo 3000 N100 was originally owned by a very young girl. Long story short, kids and expensive fragile objects dont mix. So I find myself in the posession of a rather nice computer. One problem: The screen is smashed, and it doesn't have a PSU. Being the (very cheap) geek that I am, I thought it would be more fun to turn it into a franken-laptop than to pay money and have the screen and PSU replaced.

I have a rather large collection of laptops and laptop parts. Hell I even made one explode for fun. Luckily I had a few spare screens lying around. I mean the bare screen. No backlight, no diffuser, no case. Just the screen. None of them were the right size, or had the right connectors, but I'll make it work somehow.

Another problem arose. The N100, like the thinkpad, uses a strange 3-pin non-standard DC jack. With 5 wires running to the motherboard and no way to figure out what pin is what, I just started attacking it with electricity until I saw a blip. This is very stupid and very likely to kill the laptop, but I got it for nothing so I don't give a crap. Very luckily for me, I found the pinout without killing the damn thing:

1 - Red - N/C
2 - Blue - 20VDC
3 - Blue - 20VDC
4 - Black - GND
5 - Black - GND

Wow. That was cool. Time to find the right PSU. I didn't have any 20-volt supplies lying around, but I did have a nice 19-volt supply from the armada I blew up. So I used that. Once again, stroke of luck, the laptop was able to start undervolted. It began to start up, the CCFL shocked me pretty good (next time I'll probably unplug it), then i noticed the battery was charging. Neat.

Back to the screen now. The laptop is supposed to use a 1280x800 screen with a 30-pin dual-channel LVDS connection. The screen that I decided to use was 1024x768 with a 20-pin single-channel LVDS connection. Naturally that means seeking out a pinout for both kinds and seeing if I can match them up. I ended up spending four hours on google, but I got them. I freaking got them.

Just about every LCD screen on a laptop made after 2004 has the 30-pin connector. The Toshiba Tecra 8000 which this screen came from was quite old, so it sported the older kind. Weak. Here are the pinouts:

Old 20-pin kind
1 3.3V+
2 3.3V+
3 ground
4 ground
5 D0-
6 D0+
7 ground
8 D1-
9 D1+
10 ground
11 D2-
12 D2+
13 ground
14 Clock-
15 Clock+
16 ground
17 reserved/D3-
18 reserved/D3+
19 ground
20 ground

New, 30-pin dual-channel - 3.3v
1 ground
2 +3.3v
3 +3.3v
4 +3.3v
5 nc/key
6 DDC Clock
7 DDC Data
8 A D0-
9 A D0+
10 ground
11 A D1-
12 A D1+
13 ground
14 A D2-
15 A D2+
16 ground
17 A Clock-
18 A Clock+
19 ground
20 B D0-
21 B D0+
22 ground
23 B D1-
24 B D1+
25 ground
26 B D2-
27 B D2+
28 ground
29 B Clock-
30 B Clock+

Keep in mind that there are now several variants of this pinout. They vary very slightly for the same voltage schemes, but vastly for other voltages.

VESA standard 12-volt, 30-pin pinout
1 +12v
2 +12v
3 +12v
4 +12v
5 gnd
6 gnd
7 gnd
8 gnd
9 lvds_sel
10 reserved
11 gnd
12 D0-
13 D0+
14 gnd
15 D1-
16 D1+
17 gnd
18 D2-
19 D2+
20 gnd
21 CLK-
22 CLK+
23 gnd
24 D3-
25 D3+
26 gnd
27 reserved
28 reserved
29 gnd
30 reserved

Some TV's (for example 768-line Aquos sets) use this scheme, but with 5 volts instead of 12.

VESA standard 5 volt, 30-pin LVDS:
1 reserved
2 reserved
3 reserved
4 gnd
5 0-
6 0+
7 gnd
8 1-
9 1+
10 gnd
11 2-
12 2+
13 gnd
14 clk-
15 clk+
16 gnd
17 3-
18 3+
19 gnd
20 reserved
21 lvds-sel
22 reserved
23 gnd
24 gnd
25 gnd
26 vlcd 5v
27 vlcd 5v
28 vlcd 5v
29 vlcd 5v
30 vlcd 5v

Hopefully, it will be as easy as connecting the appropriate wires and firing it up and seeing some text. If I see jibberish, I'm smashing the whole thing. One thing is for certain though. Best case scenario: The laptop assumes the screen is 1280x800 and so doesn't scale properly. Because I can't edit the bios to change the screen type, I'll have to deal with waiting for the OS to load before making the appropriate adjustments.

To perform this wiring crap, just match up everything you can. Ignore channel B, ignore DDC, be careful to not mix (+) and (-), and have at it. After soldering 16 tiny little wires, you're ready to test it.

I start it up and....



I started it up, and it worked just as I expected it to. Words came up on the screen, clear as clear could be. Apart from a large stripe across the left side of the screen (due to a rather curious cat causing damage to one of the lcd ribbons), everything lit up and everything worked great. The only small issue is like I expected, the laptop thinks its a 1280x800 screen, but the screen is 1024x768. Long story short, cropping. To fix this is rather easy, just disable panel scaling in your graphics options. For some its in the BIOS, sometimes its in windows control panel. Set your proper settings, and enjoy.

For those wondering how I wired the backlight, well located the raw LCD panels original backlight and diffuser, and replaced the inverter in the donor screen with the one that was in the smashed screen. I cut the wires, and wired the old inverter to the donor screens CCFL tube. This allows me to retain control of the inverters brightness.

Happy modding!

(pics to be added soon)
(Anonymous) on April 3rd, 2008 11:41 am (UTC)
and ?
and ? did it work ?