TROUBLE-SHOOTING and REPAIRING Personal Computer Hardware

TROUBLE-SHOOTING and REPAIRING Personal Computer Hardware
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Hardware problems usually surface at the time you are booting your PC, but sometimes occur when you are trying to access some device on your PC.
I will address some of the most common problems first, then go into a few more less common problems.
RULE OF THUMB: Always turn-off the power to your PC before connecting or disconnecting any device or cable! Also, we recommend that you use a "static" wristband before touching any expansion card or chips in your PC to reduce problems with "static electricity". NOTE: Some PCs will burn a chip on the motherboard if you plug in a device or remove a device while the power is on!

1. "Keyboard Error" - this error usually appears when booting and often is unnoticed by the user because "who really watches the boot process?". It is usually noticed when the keys you press don't reflect on the screen.
CAUSE: Keyboard is not plugged into its port, or the keyboard has died or shorted somewhere.
SOLUTION: Turn-off the power, plug the keyboard into its port, and reboot. If it is plugged in, try another keyboard in its place.
2. "Mouse Not Found" - usually appears when you are booting.
CAUSE: Mouse may not be plugged into its port. Might be because the mouse has been dropped and destroyed inside the mouse case.
SOLUTION: Check if your mouse is plugged in. If it is plugged in, try another mouse. If a new mouse doesn't work, you may have to re-install your mouse software.
In some machines with "Micronics" motherboards which have two 9-pin COM ports, you will find that some Microsoft/PS-2 (the ones with a dull gray finish and a small plug) mice will not work in the port labeled "Mouse", and you have to plug it into the other 9-Pin connector. Make sure the power is off when you do this.
3. Message: "Invalid System Disk" This may occur when you are trying to load an operating system, or when you try to boot your PC.
CAUSES:
a. No operating system currently installed on the "C:" drive.
b. No bootable partition on the "C:" drive.
c. No "bootable" partition on "C:" drive set to "active" status.
SOLUTIONS:
Use the DOS SETUP DISKETTE #1 to boot your machine. At the first MS-DOS screen where you can exit (you will see "Exit=F3" along the bottom), exit by pressing F3 twice. You should see the "A:\> prompt appear. Run the "FDISK" program from the "A:" drive. Then select option 4 to see the status of your partitions. If the C: drive is not "active", set it to "active" using the "FDISK" option 2. Then try to reboot.
If your system still doesn't reboot, you will probably need to load your operating system - DOS or whatever.
4. Message: No Operating System" or "Operating System not found".
CAUSES:
a. No operating system currently installed on the "C:" drive.
b. No bootable partition on the "C:" drive.
c. No "bootable" partition on "C:" drive set to "active" status.
d. Hard Drive (hard drive 0) may not be properly defined in the Setup (CMOS). Remember this: You should always have a listing of your setup taped inside your PC's cover. Many times, your hard drive will have the specifications for that hard drive listed on the label on the hard drive. Many systems will want you to set your CMOS to "Auto" for auto-detect, and some even want "not installed" (but this not common).
SOLUTIONS:
Use the DOS SETUP DISKETTE #1 to boot your machine. At the first MS-DOS screen where you can exit (you will see "Exit=F3" along the bottom), exit by pressing F3 twice. You should see the "A:\> prompt appear. Run the "FDISK" program from the "A:" drive. Then select option 4 to see the status of your partitions. If the C: drive is not "active", set it to "active" using the "FDISK" option 2. Then try to reboot.
Check your setup (cmos) to see if your hard disk is properly defined in your CMOS. If not, set it properly, and try to reboot.
If your system still doesn't reboot, you will probably need to load your operating system - DOS or whatever.
5. Message: "Not Ready Reading Drive A:" or someother drive.
CAUSES:
a. No floppy in drive A. or no CDROM is CDROM drive.
b. Floppy drive cable installed incorrectly. Pin 1 on wrong side.
c. Cable installed backwards.
d. Invalid Drive Size
e. A: drive has died or shorted out.
SOLUTIONS:
Place a floppy diskette in Drive A and press ENTER key.
Check the cable on the A: drive. Make sure the red edge goes to pin 1 on the drive (usually toward the power cable), and that the cable connector is on all 34 pins. Some floppy drives have an arrow and a 1 to show which side is pin 1. Then try again to read the drive.
NOTES: An IDE floppy cable has 34-pin connectors. The red edge of the cable at the motherboard normally is toward the rear of the PC or motherboard. The end of the cable with the two connectors close together goes toward the drives, the long end connects to the motherboard.
Make sure the end of the cable with the two connectors close together is plugged into the A: drive. The end connector goes to the A: drive.
6. Indicator Light on a Drive remains on and will not read.
CAUSES: Usually caused by incorrect cable installation.
a. Check the cable on the A: drive. Make sure the red edge goes to pin 1 on the drive (usually toward the power cable), and that the cable connector is on all 34 pins. Some floppy drives have an arrow and a 1 to show which side is pin 1. Then try again to read the drive.
NOTES: An IDE floppy cable has 34-pin connectors. The red edge of the cable at the motherboard normally is toward the rear of the PC or motherboard. The end of the cable with the two connectors close together goes toward the drives, the long end connects to the motherboard.
b. Make sure the end of the cable with the two connectors close together is plugged into the A: drive. The end connector goes to the A: drive.
SOLUTION: Install cable correctly.
7. CDROM will not read.
CAUSES: Could be many problems.
a. Cables not properly attached.
b. Device not properly configured.
c. Driver software not loaded at boot time.
SOLUTIONS:
Make sure the cables have the end with two connectors at the drive, and the long end to the motherboard. Make sure the red edges of the cable are on the Pin-1 side of the drive and motherboard connectors. If you have to change the cable, turn off the power before unplugging the cables.
Check your "config.sys" file. It should have a statement like this: "DEVICE=C:\CDROM\SGIDECD.SYS /D:MSCD000". On your PC the directory and the "SGIDECD.SYS" may be different, but the statement should be there.
Check your "autoexec.bat" file. It should have a statement somewhat like this: "C:\DOS\MSCDEX.EXE /D:MSCD000". Again the directory may be different.