This section of the guide is concerned with drive problems that cannot be corrected with cleaning or mechanical adjustments. To perform some of the following tests, you should have a known-good diskette that has been properly formatted. The disk may contain files, but make sure they are backed up properly-if you can't afford to loose the files on a disk, don't use that disk.

Bench Tech Tip - A common error that can happen if you have replaced or installed a floppy drive into a system is where the flat data cable has been installed reversed. You may not notice it until it is too late. Always watch the floppy drive active light and if it stays when you boot the machine on you probably have the cable reversed. If you are unfortunate enough to put a floppy disk into the floppy drive while the cable is reversed the data on that floppy disk will be destroyed.

Symptom 1.
The drive is completely dead- (the disk will not Initialize)

Check that the drive is configured properly in the system's CMOS utility. Inspect the disk itself for damage, and make sure that it is inserted properly and seated properly in the drive. Try several different diskettes in the drive to make sure it its not just a defective diskette. If you cannot get diskettes to insert and seat properly, replace the drive. If the disk inserts properly but does not initialize, check the drives power and signal cabling. Loose connectors or faulty cable wiring can easily disable a drive. Also check that the floppy drive controller board is inserted properly. If the connections are secure then use a multimeter to measure the voltage at the drives power connector. Connect the meter's ground lead to pin 2 and you should be able to measure +12volts DC on pin one. Ground your meter on pin 3 and you should get +5 volts DC at pin 4. If either or both of these are missing, try a different power cable or troubleshoot your computer power supply. Try reconfiguring the floppy drive cable by using the other (B) drives end. If the drive works then replace the cable.

Symptom 2.
The floppy drive rotates the disk, but will not seek to the desired track.

DOS might report this problem as a "Seek Error" and is generally the result of a jammed or defective stepping motor. Remove power, open the computer and remove the drive. Inspect the head positioning assembly and be sure there are no broken parts or obstructions that could jam the read/write heads. You may want to examine the mechanical system with a disk inserted to be sure that the trouble is not a disk alignment problem that may be interfering with head movement. Gently remove any obstructions you might find. If that does not cure the problem, try a different floppy drive controller cable or floppy drive controller. If you still have no luck, replace the drive.

Symptom 3.
The floppy heads seek properly, but the spindle does not turn.

This symptom suggests that the spindle motor is inhibited or defective, but all other functions are working properly.

Remove the drive and check for obstructions, make sure that there are no broken part that could jam the spindle. If there is a belt between the motor and spindle, make sure it is tight and not slipping. Do NOT add lubricating agents to the assembly, but gently vacuum or wipe away accumulated dust and dirt. Make sure appropriate power is present at the connector. Try a different signal cable, there may be a break in the MOTOR ON line. Try a different drive controller board. Try a new drive. If all else fails, replace the drive.

Symptom 4.
The floppy drive will not read from/write to the diskette.

All other operations appear normal. DOS will typically report this type of problem as a 'disk read or disk write' error. Begin by trying to read or write a file from a known good properly formatted diskette. A faulty diskette can generate some very perplexing read/write problems. If a known-good diskette does not resolve the problem, try cleaning the read/write heads. Do not run a drive with a disk cleaning diskette inserted for more than 30 seconds at a time or you risk damaging the heads with excessive friction. If this does not correct the problem then you must determine whether the problem exists in the floppy drive or the floppy drive controller or it's cabling. Try replacing the cable first, then try a different drive on the existing floppy controller. If the new drive works, replace the old drive, if not, replace the controller.

Symptom 5.
The drive can only recognize either high or double- density media, but not both.

Dos typically reports an error such as "Bad Media Type" and is almost always the result of a fault in the drive's media-type sensor. Try another floppy drive. If problems persist, try a new signal cable. (The MEDIA TYPE signal line might be broken)

Symptom 6.
DOS reports an error such as "cannot read from Drive A:" even though the diskette is fully inserted and the drive LED indicates that access is being attempted.

First make sure that the disk is really inserted properly and completely in the drive. Also make sure that the disk is working and properly formatted. You might wish to try several disks to be sure that the error is not media related. If the problem persists, the disk-in-place sensor in the drive might be defective. Try a new floppy drive assembly. In the unlikely event that this does not correct the problem, try a new signal cable or controller board. (In that order)