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Power supply help asap! Answered

i am very disapointed. i just spent 4 hours working on a atx power supply. (look at my other forum post) i did everything they said. but whenever i turn it on and run it with something, it turns off. i noticed that when i hooked up the led to the green ad black wire, it was dim. and when my supply turns off, the led keeps on. what could be my problem? i put a 10 watt 10 ohm resistor in between the 5v line and the ground. any ideas. asap. thanks

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Padlock

10 years ago

Open up the case and blow it with compressed air. My guess is that a metal shaving is shorting a line.

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11010010110

10 years ago

maybe its too large load for it. check the max current on the supply can you connect the load in portions and not all at once ? can you connect it first thru a resistor ballast (high power resistor below 1 ohm - heating elements with center taps are usually good for it) and then short the ballast later ?

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Big Bwana

10 years ago

Just hook it up to your fuel cell, you shouldn't need the resistor, your fuel cell should demand a fairly constant load from the supply with out major fluctuation's, however the power supply might turn off when you add or remove the load from it because while they allow for small load changes (( a few amps 1-2 area )) if there is a major load change that occurs rapidly, they view this a fault and shut every thing down to protect the supply and load... And your LED may remain lit for a while most SMPS have huge capacitors which will supply a LED for several minutes to maybe several hours (( depending on the supply and LED current used ))

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Big Bwana

10 years ago

Ok an ATX supply has a on / off control this is simply activated by shorting the green wire to a ground wire, and if your not using the 3.3 volt portion of the supply, connect the brown wire (( 3.3 VDC sense)) to a orange wire (( 3.3 VDC supply )) this stops it from outputing more then 3.3 VDC at any time... Most ATX power supplies will run with no load (( they have a fan for a small load on the 12 VDC side )) but a good SMPS doesn't need to be loaded it won't magically output 480 VDC with out a load... the Antec supplies won't even turn on there fan until you demand more then 100 watts... And when your playing with it, do you have 5 volts between the Purple (( 5VDC standby )) and ground while the supply is turned off but plugged in ?? And what are you trying to run on the power supply and which leads are you hooking it up to ??

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Sandisk1duo

10 years ago

that's not why it doesn't work, it's a safety feature, it's probably thinking, "OMG Something is shorting! AAHHH! Turn off!!"

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Sandisk1duo

10 years ago

short the green&black connect your device before you plug it in

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Sandisk1duo

10 years ago

um, connect the psu to something that eats power, your device then bridge the green & back, NOW plug it in