Case wiring - what's positive, what's negative?

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bitgod

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Feb 20, 2003
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All those lil case wires you get to plug into a mobo, how do you know what's positive and what's negative? They're usually orange/white, blue/white, etc...so I assume white is a constant, but which one is it?

I'm trying to troubleshoot a mobo I replaced for my sister, and ECS socket A mobo with my old Athlon XP 1800+ in it. The system will fire up for about 8 seconds, then then shut down. One thing I found was the CPU fan wasn't spinning, got that fixed now, I assume the CPU wouldn't have fried in 8 secs with a big ol Thermalright copper heatsink on it?
 
Thanks, though I was talking about the wires from the case to the mobo for the power switch, reset switch, HD LED, etc...as opposed to the PSU wiring.
 
Well, your answered helped me find the answer. I wasn't sure what I should search on, so I tried some other combos, found this on a page...

Next, sort the wires that will be used to connect to the front panel connectors on the motherboard. Your case should have wires for the power switch, reset button, speaker, hard drive and power lights. The wires are colour coded and each one is labelled. The wires have polarity, and in order for them to work you must connect the wires the right way around. The coloured wire is the positive wire, while the white one is the negative.

http://www.pcworld.idg.com.au/index.php/id;1209755529;fp;2;fpid;1294003727
 
bitgod said:
The wires have polarity, and in order for them to work you must connect the wires the right way around.
Click to expand...

MOSTLY true. Only the power and hard drive access LED are polarity sensitive. Switches, are not. They do as their name states, switch on (close circuit) or off (open circuit). On the LEDs if you connect it wrong, they don't light.

Honestly you're looking at the wrong spot for trouble shooting this PC. My first step if you're certain it's the front panel connection is to disconnect ALL the wires, and use a flat headed screw driver and just short the two pins that the power switch connects to for a split second. I'll bet you it still turns off after 8 seconds.
 
..make sure that the heatsink makes good contact with the core.. investigate capacitors on the mobo - check if they aren't blown..
 
Ya, didn't think it was the front panel wiring per se, I just noticed reading the manual again that they reversed one pair of the pins, so I wanted to make sure I had them in correctly, shooting for the easy stuff first. Don't know why I used to get it to start via the power switch, and then looking at it last night, it'd only power up after flipping the PSU off and then back on. I'll look at reseating the cpu and pulling stuff, guess I'll try swapping video cards. Caps should be ok per se, it's a brand new mobo I bought at Fry's last week. (wasn't a returned mobo).
 
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