|
|
Power Supplies Explained
Troubleshooting a PC Power Supply isn't that difficult. Various PC parts will use either 3.3 volt, 5 volt, or 12 volt. The
3.3 and 5 volt leads usually power digital circuits, while the 12
volt leads provide power to fans and drives. The common form factor used in computers
today is the ATX. This power supply has a single, twenty-pin connector.Some typical symptoms of a bad power
supply include: Dead system, partially dead system, and random
rebooting. If the PSU's fan quits working, replace it immediately. |
Computer Power Consumption
|
Component |
Requirement |
Line(s) Used |
| AGP
Video Card |
30 – 50W |
+3.3V |
| Average PCI Card |
5 – 10W |
+5V |
| 10/100 NIC |
4W |
+3.3V |
| SCSI Controller PCI Card |
20W |
+3.3V and +5V |
| Floppy Drive |
5W |
+5V |
| CD-ROM |
10 – 25W |
+5V and +12V |
| DVD-ROM |
10 – 25W |
+5V and +12V |
| CD-RW |
10 – 25W
|
+5V and +12V |
| 7200rpm IDE Hard Drive |
5 – 20W |
+5V and +12V |
| 10,000rpm SCSI Drive |
10 – 40W |
+5V and +12V |
| Case/CPU Fans |
3W
(ea.) |
+12V |
| Motherboard
(w/o CPU or RAM) |
25 – 40W |
+3.3V and +5V |
| RAM |
8W per 128MB |
+3.3V |
| Pentium III Processor |
38W |
+5V |
| Pentium 4 Processor |
70W |
+12V |
| AMD Athlon Processor |
70W |
+12V |
You can test
these leads with a voltmeter or purchase a power supply
tester.
If you have a
bad power supply, you can swap it our relatively quickly.
One rule of thumb is to buy the same size or larger.
You may need the extra power one
day. Also, be sure to spend the money on a
brand name. This is not the place to
skimp.Buy Other Computer Parts Here |
|
The pin-outs for an ATX power
supply
Pin# Color Function
1 Orange
+3.3V DC
2 Orange
+3.3V DC
3 Black Ground
4 Red +5V DC
5 Black Ground
6 Red +5V DC
7 Black Ground
8 Gray Power OK
9 Purple
+5V standby
10 Yellow
+12V DC
(11) Orange(22) +3.3V DC
(11) Brown(22) 3.3V sense
12 Blue -12V DC
13 Black Ground
14 Green PS-ON
15 Black Ground
16 Black Ground
17 Black Ground
18 White -5V DC
19 Red +5V DC
20 Red +5V DC
|
|
|
