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PSU dropping out at 10V

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  • PSU dropping out at 10V

    My sproggy mk2.5 worked without problems for two days (other than the max787 in the middle getting very hot.) Then today, the power supply no longer powers the computer (486 dx2, 4mb ram, 130mb yes mb not gb maxtor hard disk from 1993, and sb16 car.) I hear a slight ticking noise but the computer does not turn on. The hard drive by itself can be powered though. Also if I first connect one piece of the AT power, then the second colorful one, then I can sometimes get it to power on the computer. Using a stable 12V power supply from a standard 115V power supply the 2.5 powers the computer without problems.

    Note that all this is with the engine off. The car battery is now at 10.5 to 11 volts.

    In Sproggy's schematic he sai the input could be anyehere from 8 -16 volts. Why is this not working at 10.5?

  • #2
    This is a bit of a shot in the dark, but what state is your battery in? If it's only putting out 10.5 volts it sounds like it's on the way out, do you have any problems starting the car?

    And you say people actually pay money for M$ Windows? (Does what it says on the URL) (The new car, with zero rust!) (My other site)
    Total re-design underway: on the whole progress is very slow as the car is taking up too much time :)


    • #3
      Today in the morning I started the car without problems. When the engine was on the mp3 player worked fine, then it still worked later with the engine off. Looks like it was a little drained after 3 hours of battery mp3 playing.


      • #4
        I think it might be that you are putting too much load on your +12v rail.
        As the input voltage goes down the current that PSU need to operate will go up.
        One thing to make sure if using thick gauge wires to power up the PSU.
        Another thing to try is only connect motherboard to you PSU and see if it will come on...
        Those old HD need lot of current to get started that might to your +12v rail into pretection mode.

        System Comp V3 - In progress.
        Low power MB with C7 CPU, DC-DC PSU, car ECU link, USB TV, GPS, 7" TFT, Wireless, Voice.