How do I bypass the I/O switch in Dell 5150

Posted on 2009-04-28
Last Modified: 2012-05-06
My Dell Dimension 5150 wont start.  I have looked through many forums and found this to be a common problem, stemming from either the motherboard, power supply or front panel I/O switch.  I have determined the power supply is okay and now am trying to test the front panel with the power switch, but I can't find any way of testing it.  I have absolutely no money, so buying a new one and trying it is not an option. So, if any one knows, please let me know.  thanks.
Question by:w3developing
    LVL 6

    Expert Comment

    Hi.. You cn test the switch very easily by following the cable from the switch back to the motherboard - there will either be a 2-pin plugged-into the motherboard that connects to the switch or a plug with more than 2 pins. In either case, figure out which two go to the power-switch by the color of the wires and remove the plug..

    Next, use a screwdriver or something made of metal to short the two pins together - be ultra careful not to touch anything else.. If the PC is plugged in the it should start when you do this.. If the led on the motherboard is lit and the power still doesn't come on, then it's possible you have a bad motherboard.. Try unplugging everything else and taking out any cards plugged into your PC just  in case

    Author Comment

    On this specific model there is a 40 pin cable, probably due to the 2 USB ports, headphone jack and mic jack.  Any idea which pins specificly?
    LVL 23

    Accepted Solution

    This seems to be how Dell use their proprietary connector:
    - see the FNT_PNL section.

    and here's the motherboard manual:
    but it's a bit rubbish and non-techie

    So, I'd say it's pin 19 and 20 - the pins on opposite sides of the connector, just towards the centre of the bank of pins, adjacent to the missing pin.  Do you feel lucky?

    If the PC has a **reset** button, then with some wire and some jiggerypokery, you can reroute the power switch to this, and use it instead.  

    hth, Danny
    LVL 91

    Expert Comment

    i measured a dell up some time ago; here my findings :

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