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Can I use any LCD replacement screen with a CCFL inverter?

Discussion in 'General Hardware' started by El_Mayo, Jul 27, 2014.

  1. El_Mayo

    El_Mayo

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    I broke a screen on a DELL INSPIRON 1545 laptop. I checked the part number of the current broken screen and it's LTN156AT01. another sticker at the bottom says LTN156AT01-D01. There is a little Green circuit where a little 2 pin plug goes into, and I checked the part number (cn-0h251m-74921-95p-062w-a00) and it's an LCD inverter. Because I already have an LCD inverter Does that mean I don't have to buy the CCFL version of the LTN156AT01 screen and I can buy an LCD version like this or this one to replace the LTN156AT01-D01 screen? Presumably it's also a regular LCD screen that's just been inverted if there's an inverter it's plugged into?
    IMG-20140727-WA0007.jpg 20140727_112505.jpg 20140727_112511.jpg IMG-20140727-WA0005.jpg
     
    Last edited: Jul 27, 2014
  2. McSteel

    McSteel

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    You can, but perhaps not that easily. You see, the inverter converts low voltage DC into high voltage AC, which is needed to excite the gas in the backlight CCFL. An LED backlit screen would need low voltage DC untouched, but you can't reliably know if the DC that's going into the inverter is of the correct voltage or not. Suppose your panel needs 5V for the LEDs and you're getting 12 or even 19V off of the DC part. You'd end up with a fried backlight.

    I can see that the LED-backlit screens you linked do seem to have a rectifier attached so that they can convert the HV-AC back into LV-DC, but you need to ask the seller if they know for certain that the screen they're selling fits your laptop specifically. There's always the possibility that the rectifier ("CCFL to LED converter") is unregulated, and it produces the correct low voltage only if the high voltage input from the inverter is at a certain level (say 600-650V). If it's a regulated rectifier, then the input levels should be much wider (say 500-1000V RMS) and you're golden. Another solution might be to circumvent the inverter completely, but then you still want a regulated step-down circuit, to ensure compatibility.
     
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  3. El_Mayo

    El_Mayo

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    Oh okay, I don't know anything about its voltage but it's the inverter that came with the original laptop from the manufacturer. Could I swap the ccfl screen for the newer LCD style screen? Or are the connections different?
     
  4. Batou1986

    Batou1986

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    connections are very likely different, seek a direct replacement for what you have currently or expect problems.
     
  5. McSteel

    McSteel

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    The one on the second link you gave (this one) holds some promise. You see the small PCB with several white connectors mounted parallel to the PCB? That's the AC-DC converter. It having so many different input connectors leads me to believe that it's of the regulated kind, but please, do not hold me responsible if it doesn't work for your laptop. You should ask the seller if anyone has tried and reported success with the Inspiron 1545.

    Alternatively, they (the seller) may be willing to take a high-quality close-up photos of the AC-DC adapter PCB, so that we may identify the parts used, and deduce if it's the kind you need or not.

    ## EDIT ##

    Actually, this is much more likely to work, as far as LED-LCDs go, and I think this one may be the CCFL version, but you'd have to ask.
     
    Last edited: Jul 28, 2014
  6. El_Mayo

    El_Mayo

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    I'm thinking this one. Seller is apparently unable to provide me with HQ close up shots, although it comes with an inverter so I might as well replace the current inverter with the one that'll come with the screen; surely the inverter they supply won't fry the screen? Although my only reservation is that I can't see the two pin connection from the screen to the PCB like you can see in the picture I attached on my current laptop. On the bottom right just below the screen
     
  7. El_Mayo

    El_Mayo

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    Plugged in the new screen and the laptop won't boot anymore. It powers up but the hard drive eventually winds down. I've tried reseating the RAM. laptop is presumed dead :(
     

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