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mechBgon's guide to building your first PC from parts   : )

  1. Start

  2. Case prep 1

  3. Case prep 2

  4. Data and power cables

  5. Serial ATA stuff

  6. General motherboard/CPU info

  7. Testing & installing the motherboard assembly

  8. Installing the hard drive

  9. Final connections

  10. Security during Windows Setup

  11. Best practices for ongoing security

  12. Resources (drivers, diagnostics, links, online antivirus scans, antispyware resources)

  13. A brief visual glossary

Previous: Case prep, part 2

Concept break: what you need to know about IDE data cables

  • Motherboards almost always comes with data cables.
  • The red stripe on the edge of the data cables is wire #1. The drives and the motherboard each have a corresponding pin #1 on their fittings. If you go back to the picture of the rear of the CD-ROM drive, you can see that Sony marked which end of the data connector has pins 1 & 2, and which end has pins 39 & 40.
  • Most IDE cables have a "key" on the edge of the plugs, so you can't plug them in backwards.
  • IDE hard drives communicate using faster ATA100 or ATA133 protocols, and require the 80-wire IDE cables. The extra 40 wires are ground wires that prevent cross-talk.
  • Almost all CD and DVD drives communicate using the older ATA33 (or "UltraDMA2") protocol, and can use either the 80-wire IDE cables or the coarser 40-wire IDE cables.
  • The blue end of an 80-wire cable should be plugged into the motherboard.
  • If just one drive will be on a cable, plug the drive into the far end of the cable, not the middle connector.

If you need to find Pin 1 on a motherboard fitting, check the motherboard's owners' manual. The diagram above is from this motherboard's manual.

Serial ATA data cable. Note the asymmetrical opening, it only fits one way.

Concept break #2: what you need to know about floppy drives and their cables

Floppy-drive cables are often unkeyed, they could fit upside down. Look at your floppy drive's connector area for clues that reveal which end of the connector is Pin 1. Here's a Sony, and the clue is the numeral 2. That's Pin 2, and of course Pin 1 would be right next to it, so this is the end where the red stripe on the cable should go. Pin 1 might also be marked with a small triangle or line.

Worst-case scenario, if you start the computer and the floppy drive's LED light stays on constantly, then you know that you need to shut down the computer and flip it over.

Power-supply cables

UPDATE: please consult your motherboard manual very carefully for the locations of all of its power fittings. Today, there are some motherboards that might require up to four power cables, and some of the power receptacles may not look like you'd expect. READ THE OWNER'S MANUAL!

The picture below shows an older 20-pin ATX power cable. It's obsolete now, but notice that it has a latch on one side, to engage a prong on one edge of the motherboard's receptacle.

Here is a 24-pin ATX 2.0 main power cable. Notice that the last four pins are on a detachable clip-on section at the right, so this power supply (an Antec TruePower 2.0) could also be used with a 20-pin motherboard.

NEWBIE ALERT:

Note that the 4-pin segment of the 24-pin power cable is NOT THE SAME as the ATX12V plug shown in the photo below. The voltages are different, so do not plug this segment of the 24-pin plug into an ATX12V receptacle, or vice versa, or you may permanently damage your hardware.

The picture below shows the ATX12V auxiliary power cable, which primarily powers the CPU circuitry. It adds two more 12-volt and ground wires, and also features a latch on one side. If your motherboard has a receptacle for this, plug it in. Today's latest motherboards often feature a 2 x 4 receptacle that will accept two ATX12V cables, and today's high-wattage power supplies usually have the matching pair of ATX12V cables.

Larger and smaller four-pin power plugs. The smaller plugs are used for floppy drives and some high-power video cards. The larger plugs are used for some hard drives, CD/DVD drives, some video cards, and also for some types of ventilation fans.

Serial ATA power cable, which powers most types of Serial ATA hard drives.

If you buy a high-end video card, it may need an auxiliary power cable plugged into it. It's easy to forget these if you're not accustomed to needing one. The auxiliary cable is probably going to be a 6-pin PCI-Express power cable, possibly a pair of them, and the latest video cards may even use a brand-new 8-pin design. The changes in power designs make it wise to closely examine photos of the parts you're considering (Newegg.com's product photos are useful for this, as well as reading product reviews).

The high-end video cards may use one or two PCI-Express six-pin power cables like the one shown below. Some of the latest and fastest cards may use an 8-pin plug instead of, or in addition to, the 6-pin plug. I believe it's possible to use the 6-pin plugs on 8-pin cards, it just limits peak power delivery and may prevent overclocking.

The picture below shows a special Fan-Only cable, which is a feature of Antec's TruePower models, and perhaps other brands of power supplies such as Corsair and Seasonic. On these plugs, the 12-volt wire gets a variable voltage depending on the temperature that the power supply itself is experiencing. The idea is that it will reduce the speed, and therefore the noise level, of the case fans when the system is running cool. Do not power anything but fans from the Fan-Only line, do not put self-regulating or manually-adjustable fans on the Fan-Only line (because two layers of voltage reguation may stall your fan), and do not make the Fan-Only connectors power more than three fans total.

I'm going to connect the case's rear exhaust fan to one of these unused power cables, and bundle them all up so they're not all over the place.

Next: Serial ATA (SATA) stuff