I have a very interesting idea.. but is it possible?

Discussion in 'The Projects Forum' started by Marcface, Nov 8, 2009.

  1. Marcface

    Thread Starter New Member

    Nov 8, 2009
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    Well, today my HP DV2000 went and murdered itself, the amazing laptop that it was. So rather than lose my nut and break something with someone, I went and spent about 5 hours googling to work out how I could salvage the screen as a second monitor. Now, everywhere I looked all I could find were folk who weren't willing to consider the idea, stating "just buy a new screen, scrap the laptop, bla bla". But I did alot of googling, like, my face has 'Google' imprinted on it at this stage. So the screen is the LG.Philips LF141WX1. It's a 14.1" LCD screen. The objective here, is to work out how to match up the 18 connections present on the 30 pin plug inside the panel casing to the corresponding pins on a DVI connection and appropriate power supply. The connections on the LCD panel and a DVI connection are as follows.

    [​IMG]

    [​IMG]
    Now, the wiring confuses the hell out of me here, because most of those wires correspond but under different names, but the biggest confusion is the power supply. I see 2 x 3.3v VCC connections and the third is the one I'm not sure of, a 3.3v DDC connection, the one labelled 'V EEDID'. This apparently means Enhanced Extended Display Identification Data, I'm not sure which pin corresponds to this on the DVI plug though. Also, there is a small board to power the backlights, but this part is less clear. I'm not too bad with electronics but this is definitly a bit beyond my current knowledge, so any help at all would be greatly appreciated! :):) I'll upload pictures throughout and we'll see if I melt my face off or actually succeed :D
     
  2. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    It's good advice "just buy a new screen, scrap the laptop, bla bla"
     
  3. Marcface

    Thread Starter New Member

    Nov 8, 2009
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    Cute, but that defies the whole point of this being an interesting project.. thanks anyway. ;)
     
  4. BMorse

    Senior Member

    Sep 26, 2009
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    I can see 1 problem.... you are interfacing 3.3Volts (LCD) to 5 volt (DVI)....

    But if you overcome that by using the proper level shifters, I can give you some pointers on how to go TRY to connect it (I say TRY, cause it could not work!) These are just pointers so if it fails I do not want to be blamed, (If it works I want all the credit, lol ;))

    Anyways you can try it this way:

    LCD Pin #. to (DVI Pin#)

    1. Connect to ground
    2. 3.3V+ (This must be for circuit power along with pin 3)
    3. 3.3V+
    4. 3.3V+ (This has to be some logic output for controlling circuit, try powering LCD with pins 2, and 3, then use a multimeter to test ouput to see if you read 3.3volts. Either way, pins 2,3, are all definitely 3.3+ VDC)
    5. NC (as stated)
    6. to (6)DDC_CLK(SCL)
    7. to (7)DDC_DATA(SDA)
    8. to (17)
    9. to (18)
    10. to GND
    11. to (9)
    12. to (10)
    13. to GND
    14. to (1)
    15. to (2)
    16. to GND
    17. to (24)
    18. to (23)
    19. to GND
    That should be it...... but don't take my word for it:rolleyes:...
     
  5. Externet

    AAC Fanatic!

    Nov 29, 2005
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    Hi.
    Dig deep into the averlogic.com site.
     
  6. Marcface

    Thread Starter New Member

    Nov 8, 2009
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    Thanks so much for your reply BMorse! I'm in the process of constructing the cable now and labelling the wires individually. (Thank God for girlfriends :)) I've come across a bigger problem though, and it's the controller board for the backlight. This is a picture of it, I can't work out what the cables are for nor can I find any resources online to help! :confused:

    [​IMG]
    [​IMG]
     
  7. BMorse

    Senior Member

    Sep 26, 2009
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    on the LCD back light controller, the 2 pin connector on the end are ouputs to the CCFL tubes, do not touch these when powered, HIGH VOLTAGE!! And also, do not power the board without the CCFL tubes connected or you will burn out the inverter Circuit (under the plastic cover)...

    for most controllers, they should be a + and - power connections (Usually 5 volts or 12) a digital output for when light is on, and a digital input to turn back light on or off...

    Is there anyway you can take a closer shot of the 6 pin connector on the PCB?? Both top and bottom would be nice..:).

    Are those the wires originally connected to the back light controller?? (I see 7, but only 6 pins on connector.)
     
  8. Marcface

    Thread Starter New Member

    Nov 8, 2009
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    Yes it's a 6 pin connector but both of the grey wires appear to be in the same pin socket. Here's the best I could do with those pictures! The damn white PCB connector is playing games with the flash on my camera in micro shot.
    [​IMG]
    [​IMG]
     
  9. Marcface

    Thread Starter New Member

    Nov 8, 2009
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    Oh, and here's a close up of the 6 pin connector.

    [​IMG]
     
  10. BMorse

    Senior Member

    Sep 26, 2009
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    any of the pins on the 6 pin connector shorted together on the board?? If you put a multi meter on each pin and test to see if there is any continuity on any other pins...

    So far what I can decipher,

    Red/white wire could be be power for the circuits, and pink could be power to inverter, gray/s are most likely ground, white could be the logic to turn the CCFL's on or off (or logic to tell if CCFL's are on), and the Gold and Black??? I see those 2 are pulled high with resistors (r2 and r1 on the back) could be the logic to turn the CCFL's on, if there were 2 of them anyways..... How many CCFL tubes are connected to the controller??

    What wire went to pin 1 of the controller, I see that pin goes to the Fuse (F1 on the PCB), if it were the red/white wire, that would suggest power input.....
     
    Last edited: Nov 9, 2009
  11. Marcface

    Thread Starter New Member

    Nov 8, 2009
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    Hmm.. thats hella confusing.. random question, but do you think the inverter from a PC Cold Cathode setup would work in this case? Sorry if this is a stupid question, I really don't know alot about the particular setup inside the screen. Here's a picture of the inverter I'm talking about. It runs off of 12v DC.
    [​IMG]
     
  12. BMorse

    Senior Member

    Sep 26, 2009
    2,675
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    It could if its output is within specs of the original inverter.... if not either your backlight would be too dim, or if the draw is more then you could just pop a transistor on the above inverter and let out the magic blue smoke :eek: (I've done something similar trying to swap a CCFL inverter for a PC cold Cathode tube with an inverter from a flatbed Scanner, needles to say, either one is working:()..........
     
  13. Marcface

    Thread Starter New Member

    Nov 8, 2009
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    Ok so I have a wee update, I found the specs of my Cold Cathode inverter.

    3. Input voltage of inverter:12v
    4. Output voltage of inverter:680v
    5. Current draw:5.0mA


    And the requirements of the CCFL in the LCD panel.

    Operating Voltage - Min 640v Typ 655v Max 880v
    Operating Current - Min 2.0 Typ 6.3 Max 7.0 mA

    Looking at these numbers, should it work?

    Thank you so much for taking the time to answer my many questions BMorse, I've no shame in admitting I know fudge all in comparison to the majority here.
     
  14. Marcface

    Thread Starter New Member

    Nov 8, 2009
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    Update regarding using an inverter from a Pc mod Cold Cathode kit as the invertor for the CCFL in the LCD screen.

    SUCCESS!

    [​IMG]
     
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