12V lighted switch for ATX conversion

Thread Starter

bkr1969

Joined Dec 11, 2010
16
I'm converting an old ATX power supply to a benchtop supply. Overall, a very easy project, but I wanted to add a lighted power switch - http://www.radioshack.com/product/index.jsp?productId=2103602
The power supply is switched when the power supply (green wire on mine) is connected to ground. I placed these at opposite ends of the switch and the power is on/off appropriately. I attached the 12V wire to the center pole of the switch and the power supply fan slows to nearly off and the switch light flickers dimly. If I connect the green directly to the ground pole while the switch is on, the light comes on appropriately and the fan runs correctly. Switching the switch off works correctly too, but when I turn it back on...nothing. What, if anything, am I doing wrong? I've wired other ATX supplies with simple toggle switches with no problem. Am I just not able to use a lighted switch?
 

Evil Lurker

Joined Aug 25, 2011
116
Simply put my guess is the light on the switch run off the current flowing thru the switch and the green "on" wire of the PSU simply does not have enough juice to power the light.
 

SgtWookie

Joined Jul 17, 2007
22,210
The green "on" wire can't really power much of anything; if you try to power something with it, the supply will turn on.

I wired up a yellow LED to the standby 5v on my bench ATX, so I'd at least know if it was getting power from the mains; then I connected several green LEDs to the various voltages so I'd have some verification that the supply turned on.

Just a light in a switch won't tell you a lot.
 

Thread Starter

bkr1969

Joined Dec 11, 2010
16
That all makes sense. I think I'm going to have to go with a plain switch and a separate LED power indicator.
 
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