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Can I turn my lcd laptop monitor into a desktop monitor?

Discussion in 'Televisions' started by Brian0079, Aug 3, 2004.

  1. ddp

    ddp Moderator Staff Member

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    i think that is for power, maybe for backlight. check just below the sensitive area label to see if that is a connector for ribbon.
     
  2. Kreyon

    Kreyon Member

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    yes that is the 12v backlight connection, the ribbon connector is the brown item below the word sensitive in the picture, you will need a ribbon to connect that to whatever you try to output to it. (and the ribbon is essentially the 36+ pin connectors we all have been talking about)
     
  3. SkidArh

    SkidArh Member

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    The connector on the left (2 pins) is a LCD - Inverter.
    here -> http://china.pchub.com/uph/laptop/323-16451-1624/Others-K02I024.00-LCD-Inverter-General.html you can see it

    here ->http://china.pchub.com/uph/laptop/220-5272-284/Dell-Inspiron-4000-LCD-Cable-14.1-.html you can see the cable that connect the DFP and the inverter together.
    At the end you have a connector of 36 pins (20 DFP + 16 LCD Inverter)

    Is that what you have if you disconnect the LCD Monitor from a Laptop DELL Latitude.

    Now is possible connect a LCD Monitor on a VGA video card?

    I don't think so...
     
    Last edited: Oct 18, 2005
  4. jdsteven

    jdsteven Guest

    http://www.cobblestoneplaza.com/gfx/20pin.jpg[img]
    If you've completely dismantled the lcd from a notebook, when you take off the ribbon cable the pins on the lcd itself looks like this, at least for me anyway. the ribbon from these pins goes to the motherboard with the standard push connection. after looking at this connector i thought it would be easier to interface using these 20 pins rather then the ribbon connector. i've been looking everywhere and i was wondering what i'd need to allow a standard vga cable to connect this lcd to my monitor. i'm not exactly sure what kind of circuitry i need for this and checking out places like earthlcd it looks very costly. i was wondering if i could possibly looking at the wrong things or if $200-300 is what i'm gonna need to spend to do this. the lcd monitor is a hitachi TX36D75VC1CAB and came from a fairly aged sony laptop. any help would be appreciated =)
     
  5. jdsteven

    jdsteven Guest

    [​IMG]
    If you've completely dismantled the lcd from a notebook, when you take off the ribbon cable the pins on the lcd itself looks like this, at least for me anyway. the ribbon from these pins goes to the motherboard with the standard push connection. after looking at this connector i thought it would be easier to interface using these 20 pins rather then the ribbon connector. i've been looking everywhere and i was wondering what i'd need to allow a standard vga cable to connect this lcd to my monitor. i'm not exactly sure what kind of circuitry i need for this and checking out places like earthlcd it looks very costly. i was wondering if i could possibly looking at the wrong things or if $200-300 is what i'm gonna need to spend to do this. the lcd monitor is a hitachi TX36D75VC1CAB and came from a fairly aged sony laptop. any help would be appreciated =)
     
  6. Kreyon

    Kreyon Member

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    ok before I get too deep into why it can't be done by just soldering wires to pins, read this "http://graphics.tomshardware.com/graphic/20041129/index.html" it's a real good lesson on CRT vs. LCD and how LCD works (based on TFT).
    here is a NICE! Converter card for about $150 that will work for lots of monitors and input types ( this means you could even hook up the VCR or DVD to it)"http://www.baytek.de/englisch/BayView_AD1.htm"[​IMG]

    so far the converter card is the only way I have found to make this work and the price is really not that bad considering the many uses you could get after hooking it up. if you read the article from the first link it will explaine why you have to have some CONVERTER between devices to make them communicate correctly. the card is nice because it gives you a few output methods as well as a few input methods.

    but back to why it cant be done the other way.....
    here are a few quotes from the above mentioned info site....

    "So what needs to be considered when using a TFT display? The answer involves learning the basics of how DVI (Digital Visual Interface) works, which is gradually replacing the classical VGA connection between the graphics card and the monitor."

    "Classical CRT monitors are analog devices and, as such, the electron cannon that emits the electron beam - which in turn draws the image on the screen - requires analog input signals. In principle, a CRT monitor works just like any classical television set.

    It is the graphics card's job to generate these analog signals. A DAC (digital-to-analog converter) converts the digital (parallel) information provided by the graphics chip into analog signals, which are then sent to the monitor through the VGA connector. On older graphics cards, the DAC, usually referred to as the RAMDAC in the case of graphics cards, used to be a separate chip found on the circuit board. Nowadays, two RAMDACs are usually integrated with the graphics processor, one for each monitor output.

    However, the requirements changed with the advent of TFT or flat-panel monitors. This new generation of displays requires digital signal input to be able to display an image. The trouble was that at the time of their introduction, 100% of all available consumer graphics cards used the tried-and-true (analog) VGA connector. The quick-and-dirty solution was to take the analog signal furnished by the graphics card and to simply re-convert it to a digital signal in the TFT monitor, using an ADC (analog-to-digital converter). Obviously, this approach resulted in reduced signal quality.

    For every displayed picture (frame), a border area as well as the blanking area are transmitted along with the image itself. CRT monitors require the blanking area to give them time to shut off the electron cannon when it has finished drawing a line on the screen and to move the cannon to the next line, get it in position and then switch it back on to continue drawing there. The same happens once again at the end of the image, i.e. the bottom right-hand corner - the electron beam has to be switched off and repositioned at the top left corner of the screen.
    Roughly 25% of the entire pixel data is taken up by the blanking time. Since TFT monitors don't use an electron cannon, ordering the diodes to glow directly, the greater part of the blanking time is a total waste. It was only implemented in DVI 1.0 because this standard was designed with both TFTs and digital CRTs (with a DAC in the monitor) in mind.

    Blanking time is a very important factor when hooking up a TFT display using DVI, since every resolution requires a certain bandwidth from the transmitter (graphics card). The higher the desired resolution is, the higher the pixel frequency of the TMDS transmitter has to be. The DVI standard specifies a maximum pixel frequency of 165 MHz (Single Link). Thanks to the ten-fold multiplication of the frequency described above, this results in a peak data rate of 1.65GB/s, which is enough for a resolution of 1600x1200 at 60Hz. If higher resolutions are required, the display would need to be connected via Dual Link DVI, which uses two DVI transmitters together resulting in twice the bandwidth.

    NOW The REALLY GOOD STUFF!

    The TMDS (Transition Minimized Differential Signaling) transmitter sends the serial data through the cable in four different channels, one for the clock signal and one for each of the three colors. The eight bits of information for each color are transmitted as a serial 10 bit signal: eight bits for the color data, one bit to flag whether the signal transitions were minimized and one bit for DC balancing. The data itself is transmitted at 10 times the speed of the clock signal. This is achieved through a PLL chip, which acts as a frequency multiplier. This way, 1.65 GB/s of data are transmitted at a nominal frequency of 165MHz.

    At first glance, encoding the signal in a Transition Minimized way may seem counterproductive, since an additional data bit has to be transferred without resulting in an increased overall bandwidth of the transmission. The point of the minimizing step, which uses an encoding algorithm working with the Boolean operations exclusive OR (XOR) or NOR (XNOR), lies in the safer transmission of data through the copper wiring of the cable. Every alternation in current from 0 to 1 (or vice versa) creates an electromagnetic emission (EMI). The transmission minimization reduces the number of such transitions, making the transmission less susceptible to interference from other electronic devices and creating fewer electromagnetic emissions of its own.

    The tenth bit, which is used for DC-Balancing, also increases the transmission reliability. When a current is applied to a wire for a long period of time (relatively speaking, since we're talking about very high data rates here), it takes a while before the current drop off. This can lead to transmission problems, for example when only ones (data state 1 = current) are transmitted for a long period of time interrupted by a single zero(data state 0= no current). Depending on the quality of the copper cable, the 0 could be lost. The result would be an incorrectly rendered pixel. DC-Balancing is nothing but an inversion of the eight-bit data values in order to prevent overly long periods of identical data values being transmitted over the cable.

    Obviously, great pains were taken to ensure signal integrity when the DVI 1.0 standard was drafted. Another technique employed to this end is what's called differential signaling. As we noted above, a normal digital transmission of serial data over a wire is easily susceptible to interference from external electronic impulses. For this reason, two wires are used for each DVI channel (red, green, blue and clock) and the second wire carries an inverted version of the original signal. The TMDS receiver (the monitor) then subtracts the two values from one another, allowing it to compensate for interference during transmission. <--( this is why there are so many wires in the ribbon cable to connect the LCD )

    "http://graphics.tomshardware.com/graphic/20041129/tft_connection-03.html" check out the page to see the diagrams!! really good stuff!
     
  7. jdsteven

    jdsteven Guest

    iight, thx. i knew it couldn't be done directly, i just wasn't sure what kind of board i would need =D
     
  8. bytedawg

    bytedawg Member

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    One last time. I swear this will be the last attempt to clarify something that no one seems to be paying any attention to. ALL laptops, well there may be an excetion somewhere but I've NEVER seen one, have a digital signal to the LCD and typically a converted to analog signal to the 15 pin connector on the backplane. Now please pay attention here, different models of LCD screens typically have different cables or flat ribbons to connect them to the digital signal in the laptop. If you find or purchase an internal card like that made by EarthLCD that will plug into your desktop then typically it will work only for CERTAIN LCD screens. Not ALL screens will work on this card, that is why when you purchase one from any manufacturer they will have to make it to fit a particular screen, presumably the one you want to use and though this card can probably run other screens the card will more than likely need mods or you'll need to mod the screen cable. AGAIN, if you are handy you can make a convertor for your LCD if you have the DOCS and some technical expertise. YOUR laptop had one in it!!!! If it is trash, rip it open!!! Now for some shocking info that I haven't seen here. If you don't want to use the backlight for whatever reason, cut a large section out of the back of of the LCD monitor housing but be sure to make it smaller than the diffuser and don't damage the diffuser, then you should be able to use ambient light to view the screen contents. Sunlight actually works great to illuminate the backlight diffuser. Using your laptop LCD on your desktop cxan be done and you don't need to be a physicist or genius electronics engineer to make it work but is it worth the hassle when a 15" LCD monitor is well under 200 bucks. What would be fun though is connecting several 13 or 14" screens to one desktop for large screen.
     
  9. kmangwing

    kmangwing Guest

    Hey guys. Just saw this thread and thought i'd join in. My neighbor gave me a compaq presario that she broke a hinge off. The problem is that the cable snapped with the hinge. The laptop is total crap, so i figured, what the heck, maybe i can make a monitor. But like i said, the cable is snapped. Anyone know how i can connect another cable to it? or is that a lost cause.. it is a paper thin ribbon cable. Please let me know!
     
  10. kmangwing

    kmangwing Guest

    Another thing is, since the laptop is trash, could i hack the video card so it takes vga input?
     
  11. Kreyon

    Kreyon Member

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    kmangwing - if the ribbon cable is not soldered to the back of the LCD panel then it should have a connector , if that is the case then you can replace the whole cable and be done with it. if not then you would have to solder a new cable in place and more than likely will burn the connections when attempting to do this. if it does have a connector on the end (which may be hidden inside the panels casing.) then you coud replace the cable real easy.

    now for the VGA hack on the vid card.....NO. read more of the obove posts to learn why. (analog to/from digital signals need translation.)and why would you do this anyway? if the monitor is broke and the laptop is junk, then why? (maybe I missed something....)

    what you stand a much better chance of doing is getting the laptops video card to send a signal to a regular CRT monitor. ( in other words if the laptop works and the screen is just broken then take the screen off and send the signal to a CRT and have a one piece computer to work with.(most laptops have a Output to send the signal to CRT's built in.)just set this as the default and you could have a working computer again.
     
  12. kmangwing

    kmangwing Guest

    Ok, its not the monitor that isn't working, the ribbon cable going from the monitor to the laptop is busted. Also, i got a new laptop, and used the old one for a portable harddrive. besides that, even when it was working, it was crap. It is Compaq after all. the screws were falling out and stuff. So i would need a converter of some sort? Would i be able to buy one? OR could i find one in a busted lcd monitor? Thanks for the help
     
  13. kmangwing

    kmangwing Guest

    I just took the screen out and found the place the ribbon cable went. If i had known that 2 months ago, i would be a very happy man. Oh well.
    It has the 20 pin thing.
     
  14. Kreyon

    Kreyon Member

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    now that you know how it connected and have found both ends you could get a replacement ribbon cable and get it to work again if you wanted to.
    Ummmm.... compaq's aren't bad,(they're way better than Stink-pads!), and most of them do have an output for CRT on the back of them so you could still use it with an external monitor.

    I guess what I am trying to say is that if the ribbon cable is the only thing thats broke you have lots of options!
     
  15. kmangwing

    kmangwing Guest

    well, the hard drive has been forcefully removed, i cant get it back in, even if i wanted to. Also, i took out the lcd monitor, and the touch pad is gone (my fault). And my friend has a thinkpad. she accidently bashed her wood desk with it and broke the desk. BUt maybe this lady was rough with it. She not computer literate.
     
  16. Kreyon

    Kreyon Member

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    LOL :)
    ok well I guess that takes care of that! so what you have is a spare Laptop keyboard and an LCD monitor that needs a cable and a Card to be usable. look at the websites listed in previous posts to find the card that can make this usable for you, but you will still need a ribbon cable to hook the monitor up to it, but the card will accept inputs from vga,rca and some other adaptor types, it can be mounted in a box seprately or right to the back of the LCD board to be hidden by whatever you use to place the LCD in.

    the problem is that these days the technology is getting cheaper and cheaper and you can buy a 17" LCD monitor for about the same money as the Adaptor cards, so it really comes down to how much you like to experiment and play around with things, as to which way your descision would go.
     
  17. kmangwing

    kmangwing Guest

    well, the whole point was getting a flatscreen cheap. I don't get much money right now. WHat i do get i use to make beam robots and stuff for my guitar. What i don't understand is why i can't use the video card from the laptop as the adapter. Since the things busted i think i'll go ahead and try. Or can i make a converter? THanks for letting me know.
     
  18. Cheester

    Cheester Member

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    So, my laptop the Dell latitude xPi ps100 or whatever it is, has a 'Neo-magic' video/graphics chip. My impression of the purpose of this chip is to output the video signal, probably digitally, to the LCD. (To do this it, naturally, requires a driver... a piece of software that the computer loads which allows communication between itself (the computer) and the video chip.)

    My question is, where does the video signal come from that goes INTO this mysterious 'video chip?'

    My thinking: perhaps after the computer starts up and loads the driver for the chip (to get the LCD monitor working), the input signal could be 'hijacked'... replace by a video signal of my... OUR... choice. Related, and implicit question: what 'format' is this input video signal?

    cheers / che
     
  19. drspy

    drspy Guest

    Hey i have a IBM Think Pad 560 and i took it apart and it is a Hitachi LMG9925ZWCC http://www.pchub.com/uph/model/1--691/LMG9925ZWCC-parts.html It has a controler for the color and brightness conected to it but has this one paper thin conector with it besides the controler, I want to convert it to a desktop LCD Monitor what would i need to do this any help will be much appreciated...
     
    Last edited by a moderator: Nov 2, 2005
  20. Kreyon

    Kreyon Member

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    READ.
     

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