Changing from CCFL to LED Display

Discussion in 'Panasonic' started by onirakkiss, Mar 26, 2010.

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  1. onirakkiss

    onirakkiss Notebook Deity

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    The original inverter with the bulb in full brightness consumes 330mA@15.9V. To increase the battery runtime I was thinking of installing an LED-Light into the display. I was looking a long time for a small LED stripe, which can fit into the little gap of the metal bracket on the display. Finally I found it here: [​IMG]http://www.led-tech.de/en/Chip-On-B...hip-On-Board-SLIM-Module-LT-1446_134_141.html . I bought 2 of them for my CF-29 to connect them together and cut of the last 6 LEDs. They are brighter than the original CCFL! :D
    Additionally I bought also the constant current power supply
    (which replaces the inverter): [​IMG] http://www.led-tech.de/en/Chip-On-B...ply-for-COB--180mA,-30V--LT-1534_134_141.html which works very efficient and did not produce unnecessary heat and also have the possibility to regulate the brightness. :)
    The power consumption is now 110mA in full brightness! :p
    But now I have a problem: if I use the pwm controller of the toughbook the brightness is inverted, which means:
    Ur toughbook is off -> LEDs are full on
    Toughbook is on and Brightness is full -> Brightness is down
    Toughbook is on and Brightness is down -> Brightness is full :mad:

    I was trying of using an logic-inverter, but to my bad I was soldering at the PWM-pin in a unheeding moment, as the machine was on :eek:
    Now I have no signal on the pin. I destroyed probably IC106 or IC107 (in the well known schematic of CF-29 Main14 LCD I/F 5F). And at the moment I have no idea, where to find the chips on the mainboard for repair. :confused:

    Anyone can help me out?


    Pics:

    dismantling the display
    don't touch the front of the display without gloves
    dismantling the screen
     

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  2. onirakkiss

    onirakkiss Notebook Deity

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    next 6 pics:
    dismantling the CCFL-bracket
    on the pic with the connector from the inverter u can see 2 cutted wires- this are the plus wires. The next 2 wires right of them are ground and the last one is the pwm-signal.
     

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  3. onirakkiss

    onirakkiss Notebook Deity

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    And another 5 pics:
    cut the LED-stripes
    isolate the backside of them with tape
    Testpictures :)
     

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  4. KLonsdale

    KLonsdale Notebook Evangelist

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    Is this a picture of the screen with the led installed? All I can say is good job if that is the case.
     
  5. mnementh

    mnementh Crusty Ol' TinkerDwagon

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    onirakkiss -

    Well done, as usual. Are these strips wired in series or in parallel? What is the operating voltage of the full strip?

    I AM curious about these things, though I am leery of the lifespan. However... for $45-50US, it seems like not a terribly expensive experiment.

    mnem
    Let's get dangerous!
     
  6. onirakkiss

    onirakkiss Notebook Deity

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    @Klonsdale: Yes, this are testpics with the LED-stripes. Really bright! But on the bottom of the screen u can see the brighter points, where an led on the stripe is. I will also install an translucent plastic-stripe between the LED-stripe and the glas of the display to avoid this.

    @mnementh: 3 LED are in series, 9 of them = 27 LED on one stripe. My second stripe I have parallel soldered on the first stripe and u can cut every 3. LED, if the stripe is too long. They work on 9,6V@180mA. Hope they will work a long time :)
     
  7. KLonsdale

    KLonsdale Notebook Evangelist

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    This sounds very interesting, when you get all the details done would love to see a tutorial, this seems like it would help us cf-28 users whose screens are not as bright as the CF-29 with the added benefit of lower power consumption and increased battery life. Please keep us posted on your progress.
     
  8. Azrial

    Azrial Notebook Deity

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    Wow, quite a re-engineering; I am very impressed! I am sorry for you setback but look forward to reading more.
     
  9. h3lpmedic

    h3lpmedic Notebook Consultant

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    Simply amazing!
     
  10. Toughbook

    Toughbook Drop and Give Me 20!

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    Onirikkiss... With you being in the top 1% of the "wicked smart" crowd here... I'm left wondering who has enough brain power to help you. ;)

    Kudos to you! Looks like a fantastic mod and can hardly wait to see how this turns out. I don't have any spare monitors to play with but the first I do I'd like to help out.....

    Please list tutorial when possible. We'll sticky it somewhere!
     
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