Pin Positioning

Hey guys (and possibly but probably not girls)
I want to know if reversing pin positioning on a 3-pin power LED connector can have any negative effects.
I did this by accident the other day (put the connector on backwards 3-2-1 instead of 1-2-3) and the power LED changed from a brutally bright blue to a nice orange and instead of being on all the time now it is only on during memory read/write. I have run it for a few days with no negative effects.
Want to know if this could be unhealthy long term...
thanks

See attachments for pics

I am taking a guess here. Since its a diode (led), it probably has a positive and a negative side. Cathode and Anode. And diodes are biased such that they allow current to flow in one direction and not in the other.

Now I dont know whether its going to have a dramatic effect. I think at most your led will burn out

But dont take my word for it
:)

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Actually, now that I think about it, it has three leads so that means it could be made up of a mosfet. It thats the case, then reversing the sides wont matter as its symmetrical. But if its a BJT, then it will matter.

Sorry I dont know if this helped at all :sneaky:

First of all, you won't do any damage. As long as the reverse voltage isn't too high it is current which damages LEDs. Since the voltage comes from the mobo it is not going to be high enough to cause failure, and it must be current limited anyway otherwise normal use would damage the LED.

It is quite common these days to find 2 leg 2 colour LEDs, each leg being connected to an anode of one colour and the cathode of the other. The colour obtained depends on the polarity applied.

If you apply the same principle to 3 leg LEDs you could theoretically get 6 anode/cathode pairs giving 6 different individual colours, and 6 combined colours. In practice I've only ever seen 3 anode/cathode pairs, giving 3 individual colours and a single combined colour.

Without knowing which of the legs is connected to an anode and which to a cathode it is impossible to say what colours you will get, but it is possible that one combination will never light up and that could cause confusion, so it is probably best to put is back as it should be.

Thanks lynx, That's probably a better explanation ;)

i never heard of power pins that light led on memory read/write. maybe you connected led to ide pins? or more likely the red ide light is shining through the case when power led is turned off giving out that orangeish colour.

that said, you connect red led wire to voltage pin (labeled 1), try leaving it off to see if you like it better :)

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Originally Posted by optimus_prime

i never heard of power pins that light led on memory read/write. maybe you connected led to ide pins? or more likely the red ide light is shining through the case when power led is turned off giving out that orangeish colour.

that said, you connect red led wire to voltage pin (labeled 1), try leaving it off to see if you like it better :)

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It is on the right 3 pins. Just backwards.
It is either memory read/write or CPU usage. Either way, I like it better and I'm going to leave it as is. If it burns out faster, so be it.

I would still put it on the correct pins just show you don't have any other problems with other components due to voltage. You may be safe but i would play it safe and just put it in the correct way. But hey if you like it the way it is thats all that really matters.

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Originally Posted by grimms

I would still put it on the correct pins just show you don't have any other problems with other components due to voltage. You may be safe but i would play it safe and just put it in the correct way. But hey if you like it the way it is thats all that really matters.

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No other real problems that I can see, I ran it for over 12 hours with two instances of Prime95 (one on each core) and it's rock solid.

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Originally Posted by kaiweiler

It is on the right 3 pins. Just backwards.
It is either memory read/write or CPU usage. Either way, I like it better and I'm going to leave it as is. If it burns out faster, so be it.

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can you tell what motherboard do you have?

Sure, it's a Gigabyte GA-MA69G-S3H
http://www.gigabyte.com.tw/Products/...ProductID=2554
Why?

as i said i never heard of such pinouts, wanted to check if manual says something about it. unfortunately gigabyte is currently down as usual :)

that's a nice board tho, i made 690g box for a friend couple of days ago and wanted that one, but as i couldnt find it i had to go with biostar :)

Well my best guess is that if nothing has happened nothing prob will, other than burning the LED out, but prob not. As Lynx said theres not much current coming through the MoBo to those pins so no big deal I would say, cool effect if anything. Did you try putting it the correct way to see if it worked regularly now?

Yes it still works regularly as well.
Here's a pic for you Optimus.
It's the connection on the far left. The green wire is typically supposed to be on bottom with yellow on top.
And another pic just for fun to show off my 8mp digital camera ;)

8mp digital camera, used to take 1mp quality pics. :lol:

Ok, this may sound interesting to check out. I may want to try doing this myself.
On my pc, I have two leds, one is

green(stays on all the time when pc is on)
red( turns on when cpu is busy)

I would like to change the red light to something else
How exactly do the pinouts work?
I'd like to add the 3pin leds to mess with the colours.

Just so you guys know...
The activity LED is indicating hard drive access, NOT CPU activity.

A small point to be sure, but true nonetheless.

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Originally Posted by rossco

8mp digital camera, used to take 1mp quality pics. :lol:

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It was sarcasm, although it is 1.3mp :P

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Originally Posted by wrongun92

I would like to change the red light to something else
How exactly do the pin-outs work?
I'd like to add the 3pin leds to mess with the colours.

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well i'm not sure this exact example can help you. you can change led color by changing diode but as for activity, i don't think even acpi pin-outs behave that way. i personally never heard of power-led pin-out that behaves in described manner.

what puzzles me is, if i understood pic correctly (btw. thanks for pics kaiweiler, great camera :)) we are talking about green/yellow connector, meaning it's standard 3pin - 2 wire connector. meaning 3rd pin on the board is irrelevant, but i checked gb manual to be on the safe side and it's just another ground. so, with the connector flipped backward there shouldn't be any light in properly grounded case.
kaiweiler are you absolutely sure light ain't coming from some other source? i'm almost 100% certain that what you are looking at is in fact ide-led and power-led is just turned off.

could it be that its a bjt led?

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well i'm not sure this exact example can help you. you can change led color by changing diode but as for activity, i don't think even acpi pin-outs behave that way. i personally never heard of power-led pin-out that behaves in described manner.

what puzzles me is, if i understood pic correctly (btw. thanks for pics kaiweiler, great camera :)) we are talking about green/yellow connector, meaning it's standard 3pin - 2 wire connector. meaning 3rd pin on the board is irrelevant, but i checked gb manual to be on the safe side and it's just another ground. so, with the connector flipped backward there shouldn't be any light in properly grounded case.
kaiweiler are you absolutely sure light ain't coming from some other source? i'm almost 100% certain that what you are looking at is in fact ide-led and power-led is just turned off.

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Yes I am sure light is not coming from another source, it is too bright.
And it does seem to match HDD activity, as clocker previously said.

Not that it matters at this point, but when your dealing with the case front connections if its a switch, like power or reset, it doesn't matter which way since a switch is nothing more than a break in the line. If its an led, speaker or other indicator then polarity matters. Reversing the polarity on the led may not cause any noticeable problems but it could be doing something that you will not notice until you use it like with firewire or usb, you never know, it kind of depends on the mobos circuitry. I reversed an led once on an intel board and it caused problems but it was so long ago I can't remember what it did.

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Originally Posted by kaiweiler

And it does seem to match HDD activity, as clocker previously said.

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then it IS an ide led :) probably side by side with power led making you think it's the same source. it actually comes from other two pins (marked orange on pic below) and your power led is just sitting dead :) you can test it by pulling it off the board completely.

http://img153.imageshack.us/img153/8996/c01aa1.th.jpg