Identifying leads in case connectors

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Charles Lavin

Hi --

On case LEDs (i.e. power, sleep, drive) and other case connectors that have
+ and - leads, how do you identify which is the + lead and which is the -
lead?

Thanks,
CL
 
Charles said:
Hi --

On case LEDs (i.e. power, sleep, drive) and other case connectors that have
+ and - leads, how do you identify which is the + lead and which is the -
lead?

Thanks,
CL
Click to expand...

The + leads are usually one of the rainbow colors. Negative leads are
either black or white.
 
On case LEDs (i.e. power, sleep, drive) and other case connectors that have
+ and - leads, how do you identify which is the + lead and which is the -
lead?
Click to expand...

Use the diode range of your DMM to test the resistance of the LED. If
the polarity is correct, the LED will light up. It may be faint,
though, as most DMMs are current limited to 1mA.


- Franc Zabkar
 
Charles Lavin said:
Hi --

On case LEDs (i.e. power, sleep, drive) and other case connectors that have
+ and - leads, how do you identify which is the + lead and which is the -
lead?
Click to expand...

Among the pairs of leads that are polarized (i.e. have a plus lead
and a minus lead) there will be one lead of each pair that is the
same color as one of the leads in all of the polarized pairs. That
color denotes the - (negative) leads. I've seen them be white,
black, or red -- there seems to be no standard.

-- Bob Day
http://bobday.vze.com
 
On case LEDs (i.e. power, sleep, drive) and other case connectors that
have
The + leads are usually one of the rainbow colors. Negative leads are
either black or white.
Click to expand...

Also the + lead usually has a small triangle on the connector.
 
David said:
the -



Also the + lead usually has a small triangle on the connector.
Click to expand...
I don't think that's true. The small triangle is on one end to
indicated which pin is considered Pin #1. If you look at the pin out
for you 4-pin speaker connector, you will note that pin #1 is SPK- which
is not the + lead.

You will find little triangles on you floppy cables and HD cables, too.
 
Hi --
On case LEDs (i.e. power, sleep, drive) and other case connectors that have
+ and - leads, how do you identify which is the + lead and which is the -
lead?
Click to expand...

Do you want to know which wire is the positive and which one is the negative or
do you want to know which pin on the motherboard is the positive and which pin
is the negative? On mine I had wires that were red and black, wires that were
blue and white, and wires that were green and black. I assumed with the red
and black pair of wires that the red wire was for the positive lead and the
black wire was for the negative lead. I noticed the connector had a small
triangle pointing to the black wire so I assumed that that triangle pointed to
the negative wire on each of the other connectors. The actual schematic that
showed which pins on the motherboard were positive and which ones were negative
was printed directly on the motherboard itself.
It looked something like this:
Front Panel HDR
HD LED +1 -3
PWR LED +2 -4
RESET -5 +7
POWER ON +6 -8

That meant the positive wire for the hard drive LED went on pin #1 and the
negative wire went on pin #3, etc. Your motherboard manual should have a
diagram as to how the pins are numbered.
Mine was numbered like this:

9 7 5 3 1
* 8 6 4 2
 
Bob said:
Among the pairs of leads that are polarized (i.e. have a plus lead
and a minus lead) there will be one lead of each pair that is the
same color as one of the leads in all of the polarized pairs. That
color denotes the - (negative) leads. I've seen them be white,
black, or red -- there seems to be no standard.

-- Bob Day
http://bobday.vze.com
Click to expand...
I suppose it's possible someone is using red for the 'negative' but that
would be in contradiction to any known 'standard' color coding scheme
 
The said:
I don't think that's true. The small triangle is on one end to
indicated which pin is considered Pin #1.
Correct.

If you look at the pin out
for you 4-pin speaker connector, you will note that pin #1 is SPK- which
is not the + lead.

You will find little triangles on you floppy cables and HD cables, too.
Click to expand...
 
If you look at the case connector, one of the wires has a small downward
pointing arrowhead to denote the + lead.

Ray.
 
If you look at the case connector, one of the wires has a small downward
pointing arrowhead to denote the + lead.

Ray.
Click to expand...


... or the lazy way, plug it in and if it doesn't light up,
flip it over. Plugging an LED in backwards will not damage
it.
 
Ray.Milne said:
If you look at the case connector, one of the wires has a small downward
pointing arrowhead to denote the + lead.

Ray.
Click to expand...

The arrow denotes pin 1 and whether that's + or - would depend on how
someone decided to make their case connectors, but there's no 'rule' to it.

And rather problematic for cases like the one I've got where they're all
single pin so they'll fit on 'anything'.
 
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