Atx motherboard wiring diagram - Computers & Internet

For the power cables from the Power Supply? Or Power Supply, and Front Panel header on the motherboard?

For both of these you need to state the computer manufacturer name, and Model Number.
Post back in a Comment.


If you just wish a generic, one-size-fits-all explanation;

A) 20 or 24-pin ATX main power cable.

The older computers use a 20-pin ATX main power cable. As computers needed more power to the motherboard, the 24-pin ATX main power cable was brought out,

http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain20

Scroll the page down for info on the 24-pin ATX main power cable.

[ Much older motherboards (AT) used two main power cables. { In the link - Original PC main power cables} ]


B) 4-pin ATX +12 Volt power cable.
Was brought out because Processors needed more power, than the 24-pin ATX main power cable feeding the motherboard, could deliver.

Power for the Processor,

http://www.playtool.com/pages/psuconnectors/connectors.html#atx12v4


C) 4-pin standard Peripheral power cable
Commonly misnomered as 'Molex'.

Molex was a model name given by the first manufacturer, of this design of power cable connector.
The name stuck. Kind of like referring to an adjustable open-end wrench as a Crescent wrench.

It is also referred to as a 4-pin Standard Peripheral power cable, because there are two styles of 4-pin Peripheral power cables.

4-pin Standard Peripheral power cable,

http://www.playtool.com/pages/psuconnectors/connectors.html#peripheral

Generally used for IDE (PATA) harddrives, and IDE optical drives.


4-pin Small Peripheral power cable,

http://www.playtool.com/pages/psuconnectors/connectors.html#floppy

Older computers used it for power to the Floppy Drive. It's generally used now to provide power for a Card Reader.

Note that both types of connectors use the same power wires, and 2 ground wires.
Yellow is 12 Volts
Red is 5 Volts
Black is Ground

[ Also, in the ATX main power cable:
Orange is 3.3 Volts, the Green wire is the Soft Power On wire. Abbreviated as PS_ON.

Power Supply plugged into power, the Soft Power On wire is briefly touched to ANY Ground wire. This is bypassing the Power On switch.
If the computer (Power Supply) comes on, you have a bad Power On switch.
IF the computer (Power Supply) does NOT come on, you have a bad Power Supply ]

(ALL Black wires are Ground wires. They all lead back to one central Ground point.
ALL power wires lead back to one point in the power supply, for EACH power wire.

The 12 Volt power wires, (Yellow), all lead back to one point in the Power Supply.
This is the 12 Volt power rail.

The 5 Volt power wires, (Red), all lead back to one point in the Power Supply.
This is the 5 Volt power rail.

The 3.3 Volt power wires, (Orange), all lead back to one point in the Power Supply.
This is the 3.3 Volt power rail ]

D) SATA power cable
15-pin power cable for SATA harddrives, and SATA optical drives,

http://www.playtool.com/pages/psuconnectors/connectors.html#sata

[ The smaller 7-pin SATA connector is the interface cable, or data cable.

IF, you have a SATA harddrive that has a provision for a SATA power cable, AND a 4-pin standard Peripheral power cable, ONLY use the SATA power cable.

It will burn out the harddrive if you use both. It may not do it right away, but eventually it will.
I have had people state over the years, that they were using both power cables. Came back two months later to tell me their harddrives had burned out ]

More to follow in a Comment.

Regards,
joecoolvette