Question Dell Vostro 400 Strange Power Switch Problem

kkester

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Dec 8, 2013
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i”ve got an old Dell Vostro 400 minitower that I use for a variety of non-critical tasks (Windows 10 actually runs although a bit slow). Recently, the front power switch stopped working. I took it to a repair shop who couldn’t find a replacement switch so they instead wired an external switch that has a long wire the goes into the box. Recently, I find that when I push this external power switch, nothing happens. The only way to make it work is to unplug the power cord at the back of the unit and plug it back in. Usually, after doing this, the external power switch works and I’m able to turn the computer on. Any ideas?
 
i”ve got an old Dell Vostro 400 minitower that I use for a variety of non-critical tasks (Windows 10 actually runs although a bit slow). Recently, the front power switch stopped working. I took it to a repair shop who couldn’t find a replacement switch so they instead wired an external switch that has a long wire the goes into the box. Recently, I find that when I push this external power switch, nothing happens. The only way to make it work is to unplug the power cord at the back of the unit and plug it back in. Usually, after doing this, the external power switch works and I’m able to turn the computer on. Any ideas?
You say that it 'recently stopped working'. I'd believe that this replacement switch has also failed. One could prove this with a voltmeter or ohm meter while activating the switch
 
One switch is one thing going bad but two leads me to wonder if you jumped the power pins directly on the motherboard would you get the same results your now getting.

Things I would try is unplugging the 24 pin main harness on the motherboard from the power supply and than plug it back in so it can re scrape the pins and If there oxidized get a better connection.

If jumping the motherboard power pins while bypassing the power switch and re plugging in the 24 pin harness does nothing I would question the power supply.