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Thread: 4x40 LCD not working

  1. #1
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    Post 4x40 LCD not working

    Ok i got seikos 4044 18 pin LCD and hooked it up but all i get is top and third line being black and the other with nothing. I checked everything but I cant find anything wrong.

    The only thing i can think of is the Mode of the printer port, which mode should i have it, nomal or any other?
    please help
    "I'm as confused as a baby in a topless bar"

  2. #2
    FLAC DodgeCummins's Avatar
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    Do you know if it is HD44780 (Hitachi) compatible?

    For the Parallel port, most set ECP but any mode will work.

    To get info you need the right driver. A lot of LCDs are the Hitachi standard. If it isn't you will have to figure out what software will drive it (winamp plugins).

    Now assuming that you have software (plugins) to drive it, I would double check the settings, including the contrast and brightness. And check the wiring.

    If it is the Hitachi standard, I have a lot of links you can look at, otherwise I have nothing.

    ------------------
    http://www.geocities.com/mr_bubba_zanetti/

  3. #3
    FLAC DodgeCummins's Avatar
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    Okay I re read your message, my 4x40 display (hitachi) displays a black bar on the first and third line until Winamp and the plugin starts.

    I use Lorty, but there are a few you can use to test.

    ------------------
    http://www.geocities.com/mr_bubba_zanetti/

  4. #4
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    That's almost it. I turn on the computer and the lines are there and stay there even with plugins. NO DATA is being displayed. I tried lorty's and any other plug i could find, but no luck.

    I also have noticed an innconsistency with the dirrerent schematics out there, the R/S and RW wires in some are switched on the DB25 port, so that might be my problem. Where can i get the description of all of the plugs of the DB25?
    The contrast and the back light work fine so i dont think that its the wiring but I want to re check everything this weekend. Untill then if anybody has any suggestions?


    Oh, How does the LCD stand up to the cold? Will it handle it? or can it crack and do that black blood routine?
    thanks
    "I'm as confused as a baby in a topless bar"

  5. #5
    FLAC
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    Cool

    Double check ur wiring or u can get the schematic from my site
    ftp://pictures [email protected]

    abcd-1
    abcd-1
    Author of CobraI,II,III and now CobraIV.
    You can contact me on AOL instant messenger....nick is cenwesi or cenwesi3

  6. #6
    FLAC DodgeCummins's Avatar
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    Yes, on some of the schematics those two wires were reversed. (actually on a 40x4 they were reversed but on a 40x2 they were correct)

    For a quick tester try lcd print, then you will know it isnt the winamp plugin.
    http://www.geocities.com/SiliconVall...therUtils.html

    Assuming that your parallel port is not disabled or something, recheck your wires.

    I don't remember which schematic I used, but I looked at a parallel port pinout, and compared that to the schematic to find the reversed pins.

    I cannot find any links I used, I will keep looking.

  7. #7
    FLAC DodgeCummins's Avatar
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    Okay this is the schematic I used...exactly...except I had to switch (on the parallel port pinout) pin 14 and 16.

    Those are the RS-RW lines.
    http://www.members.home.net/saridnou.../LM4857-LV.gif

    Actually this site is where I got my LCD.

    Good luck.

  8. #8
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    OK, I see that in all of the schematisc people use 2 pots 10K and 100 ohm, but i have a 100 ohm thats a lil too big for my case and i would like to get a smaller one, and i was told that two of 10k would work just fine, is that true?
    thanks
    "I'm as confused as a baby in a topless bar"

  9. #9
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    OHFG, here's somtthing weird, i switched the RW RS wires and run lorty's plug in and the screen went crazy, top line solid third one had 7-6-5-4 solid blocks and the fourth one had 1 WTF?
    I tried using lcdprint but no luck, same thing with bpplcdtest.exe

    cant really think of anything that might me wrong, im gonna go and doube-double check all the wires.
    thanks
    "I'm as confused as a baby in a topless bar"

  10. #10
    FLAC DodgeCummins's Avatar
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    Question

    The 100 Ohm is for brightness, I assume that more resistance = dimmer display, but it shouldn't hurt anything. (I am guessing)

    I would defineately(sp) recheck the wires.

    Just try running LCD print.

    The lorty plug in requires some setup (not major but you have to play with it)

    Double check the voltage, and good luck.

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