Computer connnections

[mikadonovan]

This question falls under the "everything else" catagory. As I'm sure there are some computer gurus on this site & somebody can probably help me. I just replaced a motherboard on one of my PCs. The front panel connectors (HDD led, power switch, standby light etc) all have different color wires on them. I need to know how to identify positive and negative pins. On all of them the connector itself has an arrow on one pin. What does this mean?

The arrow probably means positive, but it won't hurt anything if you install them wrong. Try it one way and if it doesn't work, try it the other way. I've put together quite a few PCs that didn't have documentation for the case, and I've had to guess my way through it a few times. Also check the PC speaker connection, sometimes the wires themselves will be labeled (or at least the negative one will be black). Then you see what the arrow indicates on that connector and apply it to the rest.

[ZOOTECH]

"On all of them the connector itself has an arrow on one pin. What does this mean?"
My guess is that would be pin 1, but it is only a guess.

[mikadonovan]

That's kind of what I was figuring for the arrow, but on one of them the arrow is on black, not red. Go figure. I'll easter egg my way through it then. I just didn't want to smoke the new mobo.
Thanks for the reply.

As long as the power supply connector is plugged in correctly you won't have to worry about smoking the motherboard. (I'm sure you noticed that the power supply connector is keyed and virtually impossible to plug in wrong). Let me know how everything works out for you.

[mikadonovan]

AAHHH! That is another thing. The motherboard I am using has a 24 pin power supply connector. The power supply has a 20 pin connector, but fits into the motherboard OK with 4 pins left unused. After checking the mobo schematic the connector should have the correct voltages applied hooked up this way as in 12v, 5v and signal lines appear to be in the right spot. If I had been the originator of this project I would not be having these problems. It was givin to me as partially disassembled and a pile of parts to see if I could make it work. If I'm doing a build I fully research everything BEFORE buying new components.

You should be ok, on some motherboards the extra 4pins are on a separate connector. On power supplies with 24 pins, there are usually two connectors (one 20 pin, one 4 pin) to accommodate different motherboard configurations. If you look close you will see that the 4 pin connector can be attached to the 20 pin to make it look like one single connector.

[mikadonovan]

Not on this one. The 4 pin power connector is for the CPU and wiil not fit in the extra 4 on the main PS connection. I have everything hooked up now and will fire it up after my RAM comes in, so I am at a standstill at the moment.

[DadO]

That extra 4 pins on a 20 pin connector (main power to the mobo) are nothing else then extra power to kick in if u suffer from overload and overload can happen if u put new ATI 4870 that suck a lot of power and u have 3 cd-dvd roms plus 3 hard disk drives....ofcourse this all depends on how much is rated ur power suply. Dont go below 350W witch is standard those days.

[Juxta5]

Your motherboard is a 24 pin because it was designed to accommodate a faster CPU and a faster graphic board. If you are using an on-board GPU (graphics built into the motherboard) and you are not using a newer processor chip you can get away with power going to only 20 of the 24 pins.

Most power supplies have 2 separate power-to-motherboard plugs... these in "combination" will give you the 24 pin power. Look for a single 4 pin plug coming out of your power supply, it also may have some grooves and guides that help it fit right up on top of your existing 20 pin connector.

Make sure you are providing enough watts for all the components, case fan(s), cd/dvd, hdd, graphics board, etc, ... 400+ watts is a safe place to start.

On your front panel connectors, grounds come in black or white and sometimes both on the same case (what were they thinking?). Personally, I reference color to being positive.

My latest rebuild...AMD Athlon 64X2 Dual Core 6000+, 4 GB Ram, nVidia GeForce 8900GT, dual SATA hard drives. I was upgrading a 4 year old computer .... have fun!