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LCD garbage after 30 mins of use

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  • LCD garbage after 30 mins of use

    Hey guys...
    I've got a 20x4 lcd above my head unit. The LCD has about 7 inches of cable coming off of it, and then is connected via parallel extension cable to the computer in my trunk.
    Now I've run this LCD with only it's 7 inches of cable with my computer overnight, and everything was great the next morning. However, now that I've got it connected via the extension cable in the car, I start getting garbage on the display after a little while of use. If I then let the car sit for 2 hours, the garbage goes away. If I turn the car off and let it sit for 30 minutes, there is still some garbage, and it gets progressively worse.

    I'm assuming that there's some sort of interference happening somewhere. Perhaps you guys can point me in the right direction. Now there's about 18 feet of extension cable (belkin gold cable) running to the trunk. I believe that one of the following factors may be to blame:

    1) cable length? I doubt it, but maybe...
    2) cable is running under the subwoofer in the trunk
    3) cable is being run alongside the power wire which is running two amps in the trunk.
    4) I've used a radio shack DB25 connector/sleeve to fabricate one end of the cable myself.

    This is one of the last quirks to work out in an otherwise fabulous system =) Any help/insight/advice is much appreciated!


  • #2
    This almost sounds like an overheating problem. This could be due to the power/control module for the LCD being too warm (i.e. it may be sitting in the path of the heater).
    It possibly could be a power problem also. Are you using a regulated DC source (the computer power supply or a DC-DC converter), or are you using AC from an AC-DC inverter? I have seen visual artifacts come from both under and over voltage.
    A carputer?!? What in the hell is that?


    • #3
      Well, I'm pretty certain it's not a heat problem. It's about 30 degrees F here in Chicago, and the garbage is still there right after I turn the car on after it's been sitting for 30 minutes. I'm about to start some troubleshooting now. I'll keep you posted! Thanks for your input Scoob...



      • #4
        After a bit of testing, it seems to be a power-related problem. When the engine is not running, I don't get any problems with the display. However, the moment I turn on the engine I get garbage. I *am* using an inverter to power the computer, but I'm otherwise very happy with the setup!

        Thanks again,


        • #5
          It is also possible u have a lose wire that attaches your LCD/Parrallel cable. Double check those. When the engine is running, it causes vibration which could cause the wires to short out.

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          • #6
            Thanks for the input cenwesi. I've gone so far as to put hot glue over the connections, and made sure that there is very little, if any, stress on the connecting wires. I will check it out though... thanks.



            • #7
              Well guys... I'm kinda stumped. *cough*up*cough*

              Anyone have any ideas? Do you think a 18" Belkin gold cable would be too long? or is it likely that the interference is being caused elsewhere? (like near the actual display)

              Again, I apreciate any input =)



              • #8
                Really I would have to agree with cenwesi and suggest that you recheck the solder connections, and perhaps cut or pinched wires.

                On my 40x4 there are 2 banks of data. I assume the same for do you get garbage on all the lines, in certain parts, or at like the end of a line?

                If the entire screen fills with garbage, it is probably harder to isolate the problem than if is a smaller area of the screen.

                However I have run some plugins that would put garbage randomly throughout my screen.

                current projects


                • #9
                  Ok guys...

                  I believe that I've solved my LCD garbage problem (kick in a WOOD door...)

                  I routed the AC power cord for the computer along one side of the computer, and the parallel cable passes on the other side. Now, the cables are never close to eachother. So far it's been 2 days and I've been unable to repeat the problem. Just in case though... anyone know where I can buy a super-extra-shielded AC computer power cord?

                  Thanks for your input guys!