Bulgin LED Switch won't light up now ( I think I might have killed it)

I recently bought a Bulgin Vandal switch w/ Green LED ring, and I was testing it on a standard 200W ATX power supply for a computer; on the 12V output leads.

I attached the positive to positive, negative to negative and it lit up just fine and was on for several minutes two different occasions with out a hitch. Now, when I took the switch up to my PC I was putting it in, I attached to the power supply in the same fashion, using a yellow lead from a 4 pin molex connector (that's the 12V+) and a black lead (that's the negative -) and it flashed for a half a second and went out. I read the schematic on the website and it calls for 3 volts, as I now realize, but it was working just fine on my smaller older power supply that was providing it w/ 12v. I can tell that there is current going through the led circuit, but it just won't light up now on either power supply... Is the LED dead; as in did I fry it?

I'm thinking you might have fried it with the 12V line, and it's possible your older power supply had VERY low voltage rails, but highly unlikely. Have you tried the switch on the older PSU again yet?

I am afraid to say that yes that LED is probably dead. Of all the LED colors Blue is probably the most sensitive to overvoltage as such they often run on lower volts then the other LED colors. You should be able to dismantle the switch and order or buy a new one from any electronics store. I think even Radio Shack carries a small selection that may work for you. When you do post back here the operating voltage on it and I will tell you the ohms of the resistor you need to wire in series on the voltage side in order for it to work properly.

White and blue leds usually use 3.5-4V
red leds usually use 1.5-2.5V

Mark620 said:

White and blue leds usually use 3.5-4V
red leds usually use 1.5-2.5V

Click to expand...

yeah your right, I had it backwards thanks man.