HDD LED and Power LED

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I have two case in which the LED won't work no matter how they are plugged
into the motherboard. Can you burn out the Power and HDD LED simply by
reversing positive and negative?



Re: HDD LED and Power LED

James wrote:
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Anything is 'possible' but reversing the LEDs on the correct pins should
not kill them.

Re: HDD LED and Power LED

On Thu, 28 Apr 2005 15:11:52 -0600, "James"

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Providing you indeed had the LEDs connected to the correct
pins, AND there wasn't some gross motherboard defect or
damage, other error, no they would not be damaged by
reversal on the pins.  It's possible your board has a pin(s)
that aren't meant for LEDs that have 5V on them, which would
burn out an LED right away but generally the front-panel
pins either don't have 5V on them, OR it's an OEM setup with
an entire ribbon cable so there isn't chance of user
accidentally damaging them in this way.

I would guess that the most likely thing is you're not
trying the right pins, or maybe even the motherboard manual
is wrong, it isn't common but sometimes there does seem to
be evidence that info is just copied from one manual to

You don't mention your ability to troubleshoot this but if
you have a multimeter you could check for voltage and
polarity on the pins you believe to be for the power LED
(while system is on of course).  If you happened to have a ~
680 to 2.2K resistor, you could try powering the LED from
the power supply 12V rail & ground with that resistor in
series between one lead and the LED, as a test (or the 5V
rail but with different values) of each LED to be sure
they're working, though it might not shine very brightly
with the higher values resistors.

Since we have limited info to go on there's not much point
in more elaboration, if you can describe the situation
better and perhaps the case, the leads & plugs, and the
motherboard, (maybe a link to the manual online) that might
be the best way to give others more info to help you.

Re: HDD LED and Power LED

finger to keyboard and composed:

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You can burn out an LED if you connect it to a supply without a
current-limiting resistor. Reversing the polarity should not be a
problem, except at high voltages.

- Franc Zabkar
Please remove one 's' from my address when replying by email.

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