Seven steps to troubleshooting hard drives
Here’s a quick and proven hard disk troubleshooting process. With each point, ask yourself the question(s) that follow.
Physical connectivity – Is the drive receiving power? Is it plugged into the PC by a correctly connected ribbon cable? For IDE drives, are its jumpers set correctly? Or with SCSI drives, are its SCSI termination and ID set correctly? BIOS setup – Does the BIOS see the drive?
Viruses – Does the drive contain any boot sector viruses that need to be removed before continuing? Partitioning – Does FDISK find a valid partition on the drive? Is it active? Formatting – Is the drive formatted using a file system that the OS can recognize? Drive errors – Is a physical or logical drive error causing read/write problems on the drive? Operating system – Does your OS have a feature that checks the status of each drive on your system? If so, what is that status? Checking physical connectivity
To work properly, a hard drive needs power and a connection via a ribbon cable to the PC. If a drive doesn’t work after moving it to a new PC, after physically moving the PC, or after the cover has been taken off, start your troubleshooting by checking the physical connectivity. It’s possible for plugs to jiggle loose when moving a PC, and it’s easy to uproot a ribbon cable connection when pulling circuit boards or performing other maintenance tasks inside the case.
A hard disk works with any Molex connector from the PC’s power supply. Make sure the plug is fully inserted. Molex connectors require a lot of pressure to fully insert, and even more pressure to remove, so don’t be afraid to push hard or pull, as the case may be. Just make sure you handle the plastic connector, and do not try to push or pull the wires.
As the PC starts up, place the palm of your hand on the flat part of the hard disk. If you can detect any vibration, the drive probably has power. If there’s no movement at all, either the drive’s physical mechanism is shot or the Molex connector you have selected is faulty. Try using a different connector before assuming the drive has a problem.
Systems like the AT/LPX have a small connector that runs from the front of the case to the hard disk. On ATX systems, it runs from the motherboard to the hard disk. This enables the LED on the case to illuminate when the hard disk is in use. Don’t rely on that LED as a positive indicator as to whether the hard disk is receiving power. The light could be burned out, the wire disconnected, or the drive might be receiving power but not be connected correctly to the PC.
The other physical requirement for a drive is the PC itself. If it’s an IDE model, the drive should be connected via a ribbon cable to the IDE bus on the motherboard. Connections can also be made with a SCSI or proprietary expansion card. Secure both ends of the ribbon cable connector and make sure the connector is covering all pins. On systems where the pins are bare instead of surrounded by a plastic ridge, it’s easy to offset the connector by a row or two on the pins. If the drive is getting power but the BIOS can’t find it, try a different ribbon cable; the one in use might have a broken wire or other flaw.
Note that there are different types of hard disk ribbon cables. UltraDMA 66 and above drives require 80-wire cables. If you use the 40-wire type, the drive will be limited to UltraDMA 33 performance.
The red stripe on the ribbon cable must match up with Pin 1 on both the drive and the motherboard or expansion card. Sometimes, though, it’s not easy to locate Pin 1. Look for tiny numbers at one end of the connector. If you see a 1 or 2, that’s the end with which the red stripe should be matched. Some connectors are notched on one side while the ribbon cables have a tab that fits into that notched area. However, this isn’t always the case. Unlike with floppy drives, where the drive light stays on even if you have the ribbon cable backward, there is...
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