Hardware Reference
In-Depth Information
While older ATX tower cases use a top-mounted power supply, BTX and some recent ATX
tower cases, like the one shown in
Figure 19.23
, use a bottom-mounted power supply.
ATX-style motherboards have a 20- or 24-pin main power connector (see
Figure 19.25
)
, plus a 4- or
8-pin CPU power connector (see
Figure 19.26
). Both are keyed so they can go on only one way.
Older Baby-AT and other old-style board designs such as LPX usually have two separate six-wire
power connectors from the power supply to the board; refer to
Chapter 18
for important information
on proper installation of Baby-AT power supplies. To attach the power connectors from the power
supply to the motherboard, do the following:
1.
Plug the 24-pin or 20-pin main ATX keyed power supply connector into the motherboard
power socket. You can plug a 20-pin connector into a 24-pin socket (and vice versa) by
connecting them in an offset fashion, or you can use cable adapters to mate them up. Most ATX
systems also use a 4-pin ATX12V or 8-pin EPS12V connector.
2.
Connect a power lead from the power supply to the CPU fan if the motherboard does not have a
CPU fan power connector.
Figure 19.25. Attaching a 24-pin ATX motherboard power connector.
