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Chapter 3. Troubleshooting Storage Devices > Troubleshooting ATA/IDE Hard Disks

Troubleshooting ATA/IDE Hard Disks

Most computers, whether they're desktop or notebook, use ATA/IDE hard disk drives as their primary storage. Figure 3.1 shows typical examples of both varieties.

Figure 3.1. ATA/IDE notebook (left) and desktop (right) hard disk drives.

What causes an existing ATA/IDE hard disk to “disappear” from the system so you can't boot from it or access data on it? Any of the following:

  • The hard disk is not connected to power or the power cable is loose. If the hard disk doesn't have a reliable connection to power, it never spins up and is never detected by your system. During installation of the drive, be sure to firmly connect the drive to a power cable coming from the power supply. If you use a Y-splitter or power cable extender, be sure the splitter or extender is in good condition and is firmly connected to the power cable and to the drive. Take a good look at Figure 3.2 later in this chapter to see the right way to connect the power cable.

    Figure 3.2. A typical ATA/IDE hard drive attached to a Y-splitter power cable before installation into a system.

  • The hard disk is not properly connected to the ATA/IDE host adapter on the motherboard or add-on card. If the hard disk isn't properly connected to the interface, it won't receive the command to spin up when the computer is turned on, and your system won't boot. The 80-wire cables used by recent hard disks are keyed (see Figure 3.4) to prevent reversed connections, but 40-pin cables and some older systems don't support keying, making it possible for the cable to be installed upside down at either the host adapter or drive end.

    Figure 3.4. An 80-wire keyed ATA/IDE data cable compared to a 40-wire unkeyed ATA/IDE data cable.

  • Damage has occurred to the signal cable or power cable. Replace cables that have creases across the wires, nicks, cuts or tears, or have cracked or loose connectors.

Notebook Hard Disks Are Different

A 2.5-inch ATA/IDE hard disk used in a notebook or laptop computer uses a single 44-pin connection for power and data instead of the 40-pin connection plus 4-pin power connector used by desktop ATA/IDE hard disks (refer to Figure 3.1). In an emergency, you can use an adapter to connect a 2.5-inch drive to a desktop computer to perform data recovery.

If you're installing a new ATA/IDE hard disk but you're unable to prepare it for use, you can also have problems with power and data cables. Plus, two other possible causes join the list:

  • The hard disk could be configured as “Not present” or “none” in the system BIOS. The drive should be configured using the Auto setting to enable the drive to report its configuration to the system.

  • The drive is not jumpered correctly. The older 40-wire cables require that one drive be jumpered as master and the other as slave; some brands of drives don't use jumpers if only one drive is on the cable. On the other hand, 80-wire cables use cable select jumpers for both drives, using the position of the drive on the cable to determine which drive is the primary (master) and which the secondary (slave) drive. Now that you know what can cause your system to have problems recognizing your existing or newly installed ATA/IDE hard disk, it's time to learn how to fix these problems.

Checking the Hard Disk Connection to the Power Supply

Virtually every ATA/IDE desktop hard disk drive uses a 4-pin Molex power connector. The same power connector, by the way, is also used by ATA/IDE optical drives (CD-RW, DVD-ROM, DVD rewritable, and so forth), and a small version is used by some types of ATA/IDE removable-media drives and by floppy drives. If the power connection is not connected to a matching lead from the system's power supply, the computer will never “see” your hard disk.

Sometimes it's necessary to connect a Y-splitter to the end of a single power cable to provide power to two hard disk drives or a hard disk and an optical drive (see Figure 3.2). A Y-splitter that's not well made (thin-gauge wires, not properly insulated) can prevent one or both drives from receiving power.

Whether you connect the hard disk directly to a power supply lead or use an extender or splitter, it takes a bit of force to make a solid connection with the Molex connectors shown in Figure 3.2; make sure the drive is attached solidly to the power cable.

Don't Overload the Power Supply

If your computer has a power supply with a rating under 400 watts, think twice about using a lot of splitters to power additional drives and case fans. To avoid problems, don't use a split cable to power a processor fan, and don't use a split cable to power two optical drives (the laser and motor mechanisms in an optical drive, such as a CD-RW or DVD rewritable drive, require much more power than a hard drive does). It's acceptable to split power between a hard drive and an optical drive or a drive and a case fan, but it's better to upgrade to a higher-wattage power supply of at least 400 watts that also provides more power connectors for drives and fans.

Remember: If your hard disk doesn't receive enough power, it won't spin, and your computer won't know it's there.

Leo Says: Been Inside Your PC Lately? Loose Cables Can Happen to You!

No matter how hard I try to keep data and power cables tucked neatly out of the way in my desktop computer, I still find cables all over the place when I open my system for cleaning or hardware upgrades. Sometimes I need to disconnect a drive's data or power cable to make an upgrade. I like to use a sticky note to remind myself to reconnect the cable when I finish the upgrade. Otherwise, it's way too easy to forget.

Checking the Drive and Host Adapter Connection to the Data Cable

The second suspect in the “case of the disappearing hard disk” is the data cable. On a desktop computer, the connection between an ATA/IDE host adapter and the drive is made with a 40-pin cable (the cable itself can have 40 or 80 wires, as shown in Figure 3.4). If the cable is not connected correctly to either the host adapter or the drive, the drive will not be detected and cannot be used.

The contrasting-colored markings on the cable indicate pin 1; line up this side of the cable with pin 1 on the drive and the host adapter. In almost all cases, the location of pin 1 is next to the power connector (see Figure 3.3). Most drives also indicate the location of pin 1 on the bottom or rear of the drive.

Figure 3.3. Data cable connections to a typical ATA/IDE drive. Pin 1 should be next to the power connector.

What's to prevent you from plugging in the cable upside down? A few years ago, alas, the answer was “nothing!” A lot of novice hard disk installers goofed up and turned the cable upside down at either the hard disk or the host adapter connection on the motherboard or add-on card. An upside-down cable prevents the PC from sending the spin-up command to the hard disk, and that prevents the hard disk from being recognized. As shown in Figure 3.4, 40-pin cables are typically not keyed, making incorrect installation all too easy.

If you use 80-wire cables (as you should with today's hard disks), don't worry. As Figure 3.4 shows, they're keyed with a projection on one side of the cable (and sometimes a blocked hole for pin 20) to prevent incorrect installation.

Leo Says: Why 40-Wire ATA/IDE Cables Are Off My List

I don't use 40-wire cables anymore, even for optical drives (which are often still packaged with this type of cable for some reason). The additional wires in an 80-wire cable provide a signal ground to support faster transfer rates, making the cable more reliable for any type of hard disk or other ATA/IDE drive.

I probably have a shoebox's worth of these cables in my junk drawers, and that's where they'll stay (unless I just throw them out)!

A data cable is useless unless it's connected to a host adapter. The ATA/IDE host adapter is usually on the motherboard. Figure 3.5 shows how to attach an 80-wire cable to the host adapter. Note the markings for pin 1 on the motherboard and how the keyed cable prevents incorrect installation. There are usually two ATA/IDE host adapters, and some computers have more. Use the lowest-numbered host adapter for your system hard disk.

Figure 3.5. An 80-wire ATA/IDE cable properly attached to the host adapter on the motherboard.

Some Motherboards Make It Easy to Install a Cable the Wrong Way

Some motherboards don't surround their ATA/IDE or floppy cable connections with a plastic skirt as shown in Figure 3.5. Whether you're installing a new ATA/IDE hard disk or reconnecting the data cable after removing it temporarily for an upgrade, it's very easy on such motherboards to incorrectly connect the cable to just one row of pins or to miss some pins entirely. These types of cabling faults also prevent the drive from being detected and can lead to bent pins. In such cases, look for a marking on the motherboard or in the instruction manual that indicates the location of pin 1 and connect the end of the cable with the red stripe (refer to Figure 3.4) to pin 1.

Avoid problems with all types of ribbon cables by using a flashlight and a magnifier to help you see the cable and the connector during installation.

Configuring ATA/IDE Drive Jumpers

When you took the PC tour that's the highlight of Chapter 1, you might have been surprised to discover that an ATA/IDE cable can support two drives. When you install a new ATA/IDE hard disk or other drive, how does the computer tell which drive is which?

Unlike a floppy drive cable, which uses a twist at the end of the cable to indicate drive A: and drive B:, an ATA/IDE cable is a straight-through cable. An ATA/IDE drive is configured as master or slave with jumper blocks on the rear or bottom of the drive. The position of the jumper blocks and the type of cable used determines which drive is the primary (master) and which the secondary (slave) drive. These jumpers are used in the same way on any ATA/IDE device, including optical and removable-media drives.

ATA/IDE drives have three basic configurations that can be selected with jumper blocks (see Figure 3.6):

  • Master (MA)

  • Slave (SL)

  • Cable Select (CS, CSEL)

Figure 3.6. The jumper pins and jumpering options available for Western Digital hard disks.

Figure 3.6 shows the most common jumper location and the various jumpering options supported on a typical hard disk.

Other brands of hard disks use slightly different jumper block configurations; be sure to follow the labeling or instructions for the particular hard disk you are installing or troubleshooting.

Leo Says: Got Questions? Ask the Drive Vendor!

To learn more about the drives in your system, including performance, jumper settings, and setup utilities, check the manufacturer's website. Major desktop hard disk drive makers include the following:

Different jumper settings are recommended for 40-wire and 80-wire ATA/IDE data cables. Table 3.2 helps you figure it out.

Cable TypeDrive Installed AsHow to JumperWhich Cable Connector to UseJumper Original Drive As
80-wireSlaveCable Select or Slave[1]Gray connector (middle of cable)Cable Select or Master[1]
 Only drive on cableCable Select, Master, or single drive[1]Black connector (end of cable)N/A
 MasterCable Select or Master[1]Black connector (end of cable)Cable Select or Slave[1]
 Only drive on cableMaster or single drive (check drive manufacturer recommendation)EitherN/A

[1] With 80-wire cables, we recommend you try Cable Select first. If you have problems with drive recognition, use Master or Slave settings as shown in the table. Drive recognition issues are more likely if you are mixing different brands of drives on the same cable.

Before You Change It, Write It Down!

If you need to change the jumpering or cable position of an existing drive when you install a new one, write down the original settings. Note that any drive plugged into an ATA/IDE cable, even if it's an optical or removable-media drive, follows the rules in Table 3.2.

Here's how to apply these settings when you install a new hard disk or other ATA/IDE device:

  • Master/slave— A drive jumpered as master will be the primary drive on the cable; if you have your hard disk and optical drive on the same cable, the hard drive should be jumpered as master, and the cable should be plugged into IDE connector number 1 on the motherboard.

  • Slave— A drive jumpered as slave will be the secondary drive on the cable. If you have your hard disk and optical drive on the same cable, the optical drive should be jumpered as slave.

  • Cable select— The position of the drive on the cable determines which drive is master and which is slave; Cable Select requires an 80-wire Ultra ATA cable. Some computer vendors use specially designed 40-wire cables that support Cable Select. Note that you can also use Master and Slave settings with 80-wire cables.

Leo Says: Color-Coding for Easier Cable Installation

Almost all 80-wire ATA/IDE cables are color-coded to help you figure out which connector to use for each drive and the host adapter. Use the blue connector for the host adapter on the motherboard or ATA/IDE add-on card. Some motherboards even use blue plastic for some of the ATA/IDE host adapter connectors to make matching the adapter to the cable as easy as possible. The black connector on the other end of the cable is for the primary (master) drive, and the gray connector in the middle of the cable is for the secondary (slave) drive.

Note: Some cables do not use the color-coding described here, but all ATA/IDE cables are made with the primary master connector on one end, the motherboard connector on the other, and the slave connector in the middle.

Checking a Laptop/Notebook's Hard Disk Power/Data Connection

We mentioned earlier in this chapter that a laptop or notebook computer's 2.5-inch hard disk drive uses a single 44-pin connection for power and data. The hard disk might plug into a fixed power/data connector or a flexible cable.

If you actually use your laptop or notebook as a portable computer and move it around frequently, the hard disk's connection to the notebook's motherboard could become loose, causing the hard disk not to be recognized at startup.

If the hard disk is accessed through a removable cover on the bottom of your portable computer, you can follow this procedure to check the connection:

Shut down your computer.

Unplug it.

Turn over your computer.

Use a small screwdriver to remove the retaining screw holding the cover and the hard disk in place. Figure 3.7 shows the relationship of the retaining screw and the hard disk as seen from the hard disk drive bay.

Figure 3.7. Detail view of a 2.5-inch ATA/IDE hard disk and its retaining screw.

Slide the hard disk out of the computer.

Reinsert the hard disk, making sure it connects tightly to the host adapter power/signal connector in the drive bay. Figure 3.8 shows a top view of the hard disk, retaining lug, and host adapter connector.

Figure 3.8. Reinserting a portable computer's hard disk into the drive bay and host adapter.

If you need to install a replacement hard disk in a portable computer, see “Upgrading a Portable Hard Disk,” this chapter, p. 210, for complete instructions.

Close the access cover.

Reinsert the retaining screw.

If the hard disk cannot be accessed from the bottom or side of your portable computer, check the manual or the manufacturer's website to learn how to check the hard disk connection. You might need to remove the keyboard or other components to get to the hard disk.

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