Check the CMOS Setting
Occasionally, the CMOS settings for floppy disks cause problems with drive operations. Any of the following errors indicates a possible CMOS setup problem:
General failure reading drive A: (or B:)
Not ready error reading drive A: (or B:)
Insert disk for drive A: (or B:) and press any key when ready
BIOS makers often use the 3.5-inch high-density disk drive as the default CMOS setting for the A drive. With this BIOS, failure of the CMOS battery, or even accidental erasure of the CMOS, will still allow most floppy disks to work. Always double-check the CMOS if you are experiencing a recurrent floppy disk drive failure. It is quick, easy, and might save you time.
It is possible for the CMOS to be corrupted by a software or hardware conflict and yet appear to be fine. If all else fails, reset the CMOS and reinstall the CMOS setup (check the motherboard manual for the jumper or disconnect the battery).
Check/Change the Floppy Disk Drive Cable
Cables wear out, work themselves loose, and are sometimes improperly installed. Check out both the data cable and the power jack as causes of the errant floppy disk drive before moving on to the controller.
Change the Floppy Disk Drive Controller
Floppy disk drive controllers are durable and highly resistant to failure and therefore should be the last components to blame. Left alone, they generally cause no problems. However, if they have recently been handled, such as during a move or repairs to the computer, they can be suspect. They are extremely sensitive to shock and static discharge.
In the event of a loose data cable or power plug, the POST (power-on self test) will return "FDD Controller Failure" or "Drive Not Ready" errors. (For more information about POST, refer to Tutorial 6, "Primary PC Components.") Verify all the connections and try again. If the connections are good, try removing and reseating the controller (beware of electrostatic discharge). If the same errors continue, replace the controller. Floppy disk drives and controllers are inexpensive.
When replacing a floppy disk drive controller (see Figure 8.4), keep in mind that most of these controllers on pre-Pentium machines are bundled as part of a combination I/O card. These cards include some (often all) of the following: hard disk drive controllers, serial ports, parallel ports, and joystick ports. If the new card contains any duplicate ports (they already exist elsewhere on the computer), a potential for conflict will exist.
Figure 8.4 I/O card with floppy disk controller
Be sure to disable all other devices on the card that are already installed on the computer when installing I/O cards. If not disabled, the I/O card can cause conflicts. If you have a new card with improved devices, disable or remove the older item.
Replace the Floppy Disk Drive
When replacing floppy disk drives, be sure to throw away the old drive. Floppy disk drives are inexpensive compared to other components in the computer. Consider purchasing them in quantity and saving money. It is not a bad idea to have a spare floppy disk drive and I/O card available for testing purposes.
As a rule, floppy disk drives fail more than any other part of a computer system except the floppy disk itself.
The following points summarize the main elements of this lesson:
The 3.5-inch floppy disk drive has become an industry standard.
Floppy disk drive technology has not changed much over the years.
Floppy disk drives fail more than any other part of a computer system. Floppy drive parameters must be properly set in the system CMOS.
When a drive fails to read or write, first check each individual medium, then the CMOS settings, and cable; as a last option, replace the drive itself.