Turn a Broken Laptop Screen Into a Portable Light Table for Drawing

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Introduction: Turn a Broken Laptop Screen Into a Portable Light Table for Drawing

About: I like to make stuff

A friend donated me this old laptop, which had a broken LCD. The laptop was old but it worked just fine. I had no intention to spend money to get it repaired, it just would not worth the money. Instead I just removed the screen from the body of the laptop and used the laptop as a HTPC connected to a TV.

Then the screen part was pretty much useless, I could have just trashed it, but I just kept it, just in case I could do something with it. Then I had this idea that I could turn it into something useful.

It turned out that it is very easy, and very useful if you're into drawing. It is a light board/table for drawing, it is very cheap and portable, you can easily carry on your backpack with your books.

Step 1:

Take the old laptop apart, and separate the screen completely off the body of the computer.

Step 2:

Remove the LCD itself from the plastic housing, then start to pry open the metal bezel. There are some screws you need to remove and then some retaining clips.

Step 3:

After removing the metal bezel, you can remove the broken LCD from the rest of the LCD assembly.

Step 4:

The driver board will come off with the LCD.

You will be left with the backlight, try to not touch the layers.

The backlight is made of a lamp CCFL in this one or LED strip, reflective sheet, a guiding glass, some fresnel films, and diffuser films. They have a very specific order, orientation and side. Just keep then as is, or it will be very hard to get then in the correct way later.

Step 5:

Now we will work with the backlight circuit.

This screen have a CCFL lamp, this type of lamp requires a Inverter board to light up. This board is attached on the bottom of the screen, you can just use this original board.

If you have a more modern screen with led backlighting, It will not have a inverter board, you easily make then work as well. You will need to build a led driver circuit, and if you want then to be dimmable a PWM circuit will be required.

Step 6: Inverter Board Pinout

I reversed engineered the inverter board to find the correct pinout.

What I did was, the board have a controller IC, I looked for the data sheet of that IC and found its pinout description, so I traced where the pins of the connector would go to which pin on the IC.

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Step 7: More on R.E.

Hope this can get you some hints on how to reverse engineer part of the circuit in order to find its pinout, because every board is a little bit different.

This is a picture of a inverter board a user asked on the comments.

He sent a picture of his board. The main device is this BD9825, search for it on google followed by the keyword "datasheet", what you're looking for it is a PDF document containing all the information about this chip.

http://pdf1.alldatasheet.com/datasheet-pdf/view/13...

The data sheet contains a description of each pin. Look at your board, the chip should contain a marking on one of the 4 corners a little dot indented, or a U groove in one side. This indicates pin 1. To make things easier rotate your board and orient this on your top left. Then count the pins counter-clock wise.

   ___  __
1-| * \/  |-6
2-|       |-5  This is how you would orient and count pins on a chip.
3-|_______|-4    

The easiest is always to find what is the GND (Ground) pin. The data chip specify GND as pin 15, count the pins and find out which pin is the 15, then follow the trace coming out this pin until it reaches one of the pins on the connector on the side, then now you know what this pin is GND. If it goes to a via follow it on the other side, if it goes underneath something you can't see were it goes, the make you best guess were it pokes out, the use a multimeter to check continuity to know if your assumption was correct.

I did basically the same with the other pins.

The GND should be very straight forward from the pin to the connector, using large traces, or ground planes, and maybe attached to multiple pins.

VCC should be a thicker trace as well, should contain one or more bypass capacitors (beige retangular devices with 2 pads) across VCC and GND, may have a in series inductor (looks like a black rectangle probably without a number on it, you multimeter should read near zero ohms if it is a inductor), and may contain a fuse in series (there are black, white, or green fuses, but should read 0 ohms).

The other Enable/Standby Adjust/Dim pins should be thinner traces coming out of the IC and will probably contain a resistor/capacitor network, to make it simpler just follow the board traces, if the traces ends on a component, continue following the trace after the resistors (black ones, with 3 digits on it) not the capacitors (yellowish ones), the capacitors will probably end to ground.

This board was different than mine, it has a STBY instead of ENABLE, and DIM instead of ADJ, but this shouldn't make much difference apart from labeling. But the data sheet is not very clear about what the levels are for DIM.

The VCC voltage should be the same as the stock power supply of the laptop it came from.

Step 8: Aditional Circuit

To power the inverter board it require 19v, and 5v logic.

So I came up with simplest circuit in order to make it work.

A low power 5volts linear regulator, to provide logic HIGH to the enable pin and a variable potentiometer to provide the analog input to the dimmer IC.

Step 9:

Solder the circuit to a perf board, and test if it work.

Step 10: Fitting Everything

After cutting the perf board, make sure it will fit inside the case.

Make sure it is not touching any metal, and hot glue everything.

Step 11:

You can mark the tip of the potentiometer with white-out, and touch the bezel to know were to cut a whole.

I used a screwdriver to dig a whole in the plastic and enlarge it with a knife. If you find hard to make a whole in harder plastics, just heat up a screwdriver with a fire, and melt a whole.

Step 12: Glass

I took the broken LCD to a Glass Store and bought a glass sheet of the same size. It was a bit thicker though about 3mm, but I could fit it inside the original lcd assembly.

It was very cheap, about $ 2.50.

Step 13: Feet

Add some silicon/rubber feet on the other side. You don't want it sliding around.

Step 14: Final Result

Here is the final result.

5 People Made This Project!

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54 Discussions

Where do you study about these?

0
user
eisou

1 year ago

Thank you, made it. But without a case yet.

invertor TBD484NR with MSC1697 controller has the same pinout.

1 reply

do you have the pinout for the msc1697? i have a ynv-w15 inverter here, and it has a msc1697 controller

Hi, I am a noob on electronics but you have explained it very well and I want to try it. My doubt is with the capacitor of your scheme. Why is there? Is it essential? What specifications does it have to buy one? Thanks!

is it possible to skip step8? the additional circuit? or light it up without inverter?

These are a few LCD displays I had to work with. You will note, I bypassed the adjustable intensity altogether. I did nothing fancy, just reverse engineered what pins to connect to what outside sources and viola! the screens lit up!

The two pins connected together in all the models I have listed below may be played with to get an adjustable dimming. I don't know how.

Make Model PCB CN1 pins Usage Chip Used length
Acer Extensa 5420 P1 blk +19vdc MP1010BEF 13”’
P2 brn +19vdc
P3 red +5vdc
P4 org +5vdc
P5 yel gnd
P6 grn gnd

Compaq Presario 1610 P1 red +19vdc ti5001c 10”
P2 blk +19vdc
P3 brn +5vdc
P4 org gnd
P5 yel gnd
P6 wht +5vdc

HP Pavilion Ze4300 P1 blk +19vdc OZ960S 12”
P2 wht +5vdc
P3 gry +5vdc
P4 brn n/c
P5 shd gnd

HP Pavilion dv9000 P1 pur +19vdc OZ9910 15”
dv6000 P2 n/c n/c 13”
P3 blu +5vdc
P4 gry +5vdc
P5 wht gnd
P6 n/c n/c

Toshiba unknown P1 grn +19vdc OZ9910SN 13’’
P2 blu +19vdc
P3 rd-w +5vdc
P4 gr-b +5vdc
P5 ye-b n/c
P6 red gnd
P7 org gnd



LCD DISPLAY PCB CN1 pins Usage Chip used CCFL “
Hitachi TX39D89VC1FAA P1 grn +19vdc MP1015 13”
P2 blu +19vdc
P3 pur +5vdc
P4 gry +5vdc
P5 wht n/c
P6 shd gnd
P7 shd gnd

Does the inverter board always need 19V? Does this circuit work with all the inverters?

Hi Guys, if someone could help me find a data sheet for my chip that would be much appreciated! Thanks!

2016, 6:54 PM.jpg
1 reply

I don't have a screen from an old laptop, but I do have an old flatscreen from an old computer. Do you know how to make that into a light table? The power goes directly into the screen from the power outlet. My problem is, that when I turn it on, it says NO SIGNAL and shuts down. How do I make the light stay on?

1 reply

if you still have the monitor and plan to do this send me a dm, i may be able to help bud

I wrote you through private message. I hope that you can help me

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1 reply

Check out Step 7, there is a video with instructions on how to figure out the pinout of your inverter by yourself.

I also have some trouble trying to find the data sheet of the chip there are 3 rows and I can't tell which one is the right number and non of the 3 numbers give datasheets..

20160622_115907.jpg
1 reply

If someone could help me I it would be greatly appreciated thanks

I got LCD inverter " M300NINT-B V1.0 " with the IC of MP1010 .... but the problem is the LCD inverter connector has a 12 Pins and the IC is too far from the connector ... can you help me to figure out the schematic of this.Thanks :D

Hello! I would like to use an led display from the hp g62-460tx laptop however, I have no idea on how the led driver circuit is constructed. I failed to find any tutorials or other material on google (all I could find were tutorials on led driver circuits for single or a few led light bulbs) to assist with the driver circuit.

Could someone please direct me to a resource which I could use to construct the led driver circuit for my laptop's led display?

Any help is greatly appreciated.

1 reply

You can figure out how many leds are in series and in parallel on your backlight, then just build a constant current led driver, or even get one of-the-shelf, or a simpler cheaper resistor dropper, current limiting, energy inefficient but it should be fairly easy that everyone could build one.

I absolutely cannot seem to find a datasheet for my inverter (Sumida IV11145/T-LF on the board, mp1017ef and/or mps 0511 on the controller, just fyi). I was curious what you thought about grabbing one of these 'universal' inverters for the project: http://www.newegg.com/Product/Product.aspx?Item=9SIA76H2GT4831&cm_re=universal_lcd_inverter-_-9SIA76H2GT4831-_-Product

1 reply

I was considering one like your newegg one.

http://tinyurl.com/AmazonCCFL-LCD-4-lamp-inverter

The universal inverters should work and simplify hook up. I was told by a retailer that a 4-lamp unit would even handle just 2 lamps if that's all you need it for. You know how many lamps you have by how many connectors are hanging from the bezel. I'm modding an AC LCD monitor to run on 12vdc and just ordered a two lamp module which matches exactly.


http://tinyurl.com/AmazonCCFL-LCD-2-lamp-inverter