Power Connectors
All power supplies provide two types of power connectors. The first powers the motherboard and differs according to form factor. The second powers drives and other internal peripherals, and comes in two varieties, which are described below. Tower/AT and Tower/BAT power supplies include a third type of power connector—a high-voltage cable that connects the power supply to an external main power switch.
AT Main Power Connector
Table 26-6 lists the standard
AT Main Power Connector
pinouts used by all AT power supply variants, including
Desktop/AT, Tower/AT, Desktop/BAT,
Tower/BAT, and
LPX.
PC/XT power supplies use the same pinouts, except that pin P8-2 is
unused. In addition to supplying various standard voltages, this
connector includes a special-purpose pin. Pin P8-1, PG, carries the
Power Good signal, which the power supply asserts once it has started
and stabilized. The motherboard will not attempt to boot until the
power supply asserts PG.
Table 26-6. Standard motherboard connector pinouts for an AT power supply
|
Pin |
Color |
Signal |
Pin |
Color |
Signal | |
|---|---|---|---|---|---|---|
|
P8-1 |
orange (white) |
PG |
P9-1 |
black |
ground | |
|
P8-2 |
red |
+5V |
P9-2 |
black |
ground | |
|
P8-3 |
yellow |
+12V |
P9-3 |
white (blue) |
-5V | |
|
P8-4 |
blue (brown) |
-12V |
P9-4 |
red |
+5V | |
|
P8-5 |
black |
ground |
P9-5 |
red |
+5V | |
|
P8-6 |
black |
ground |
P9-6 |
red |
+5V |
Note that P8 and P9 are separate connectors from the power supply, but mate to a combined connector on the motherboard.
Warning
The P8 and P9 connectors are individually ...
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