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  • CheesyHowards keypad...

    CheesyHowards said :
    I have installed and mp3 player in my first car which is an old fiesta. It rocks when it works. But when i switch on i have to remove my keypad and replug it in to get it to work.
    Any help would be appriated.

  • #2
    Lee says:

    What sort of connector does it have?
    Does it do the same when you use a normal keyboard?
    Can you see any cracks around the keyboard socket on the mobo? Maybe you should try resoldering it anyway?
    Have you tried a different keypad?
    Are you using any extension leads?



    • #3
      If you're using a std. AT-keyboard or numberblock, this problem can be caused by a grounding problem.
      ...Unix, DOS, and Windows XP
      (also known as the Good, the Bad, and the Ugly).


      • #4
        Actually, I have the exact same problem.
        But to fix it I usually have to turn the computer off and back on.
        I thought it was a power issue, maybe that the inverter does not surge enough power during startup??
        Any tips for both of us would be nice!
        Its a number keypad hooked up through a ps/2 extension cable. Everything works fine upstairs in the room, so I don't think its a hardware/bad keypad/bad connectors problem.

        What you do mean by a grounding problem?
        and more importantly how can you fix it.
        This is the one thing preventing my mp3 player for the car from being perfect! (for me)


        • #5
          What do i mean with grounding problem:


          In every keyboard there's a small micro processor. It is (usualy) a very dumb device with no protection at all. When it crashes it does'nt "boot" again. You have to power it down (pull the plug of the keyb) and restart it (plug it in again).
          This is also the reason why some older keyboards stop working when you get a electrostatic discharge.


          As you say you use an inverter, it's likely that it's not strong enough or just bad quality. An inverter ususaly generates not real sine waves but "rectangular" waves it is possible that the power supply of the PC doesn't start up cleanly.
          This can lead to voltage problems when the motherboard/processor is starting up, and the supply for the keyboard get instable. The keyboard micro crashes, and we have your symptoms...

          What can you do ?

          Because you're using an inverter: not much.
          Maybe you shold try another inverter. Try the next stronger one.

          Maybe it helps when you start the inverter a few seconds before the PC. This can be done by timer relays, which are made for keep the interiour light on after you left the car.
          Some of them have even adjustable time spans.
          You might get in a good car-technics or electronics shop.

          That's all i can tell you, hoe it helps...

          ...Unix, DOS, and Windows XP
          (also known as the Good, the Bad, and the Ugly).


          • #6
            Please ignore the first line of my last message...
            ...Unix, DOS, and Windows XP
            (also known as the Good, the Bad, and the Ugly).


            • #7
              Very good point about letting the inverter "warm up" its a fact that the inverter has to "prime" it self before it can be used.


              • #8
                Okank thanks for the explanation.
                But you said grounding problem.

                Your explanation pretty much involved the inverter and didn't mention the word "ground" anywhere so I'm still wondering what you originally meant by "grounding" problem because I was hoping it could be fixed by grounding something somewhere


                • #9
                  I purchased a better inverter (300 W) and the problem went away.
                  Thanks again


                  • #10
                    Sorry for the delay... But sometimes i have to work to get money for my player !

                    Regaring your question on "grounding problem":

                    If you use a (good) dc/dc supply which has seperate "ground's" for input and output it is possible (and highly probable) that there's a difference between them. You can check this by measuring the voltage between the two ground signals.
                    This differendes may result from the load at the secondary side (output) of the psu, from the car's electric system and even from the operating environment of the psu. I mean temperature,humidity and all that.
                    If you're using such kind of psu you should take care that the secondary electric circuit (the pc) has no direct contact with the primary circuit (the car).
                    This can be quiet difficult, just think of the audio cables, mountig screws...
                    If there is such contact between the circuits it CAN lead to problems like your's. But as you wrote that you're using an inverter I dropped this thought...

                    PS : The insolation can be done, and in my oppinion it pays off. You get a very clean audio signal with (almost) no distorsions caused by the digital hardware.

                    All you THEN need is: A good head unit and speaker system...

                    I hope i fulfilled you need of knowledge...

                    ...Unix, DOS, and Windows XP
                    (also known as the Good, the Bad, and the Ugly).


                    • #11
                      FYI: Most DC-DC PSUs don't have separate grounds; they usually share a common ground with the 12V input. Even if your PSU had its own floating ground, the PC's soundcard uses the same ground as the motherboard and all the peripheral cards, etc, so digital noise can still find its way to the low-level outputs.

                      Much of the "digital noise" heard is a result of poor shielding and board design methods used by the manufacturer of the sound card. I have at home a sound card costing several thousand dollars made by Antex Electronics that has an aluminum enclosure around both sides of the DAC and output stages. This card outputs studio-grade quality from a standard PC.

                      The only way to completely remove all digital noise would be to have separate analog and digital grounds, which PCs do not.

                      The best way to get low noise with common hardware is to use a good sound card and make sure things are well shielded and quality cabling is used.

                      Jason Johnson
                      Yorba Linda, California

                      MPC Phase IV - *** PENDING ***