Hardware/Network Difficulties

Common Problems With Hardware

Hardware failures lead to frustration, and often a loss of data, but  they can generally be fixed, and data restored, in a reasonable  amount of time.  While these problems are probably best handled by  a certified technician, the following information is presented so  that you may understand the problems that can arise.        

Hard disk failure

When you see the message "Unable to access drive C" you know you  have a hard disk

failure.  This may be repaired electronically,  through reformatting, or may require the

replacement of the hard  drive.

In a computer system, most parts work electronically, with no physical movement.  The hard disk drive is the exception.  It has  metal platters which spin on a shaft, with bearings at the top and  bottom.  These spin at very high speeds, for the entire duration of  time during which the machine has power.  Consequently, there will  be a small degree of friction, and ultimately wear.  In addition,  the heads move back and forth across the surface of the platters at  a very high rate of speed.  Ultimately they will have their  alignment changed.

Finally, the magnetic media on which data is  written is like recording tape.  It is written, and re-written  thousands, of times.  Eventually its recording accuracy may become  insufficient.  As a result of any, or all, of these factors, the drive will  ultimately fail.  There is no predictable time when this may happen.  The same model drive, by the same manufacturer, may have life spans that last from one, to five, years without difficulty.

Memory Chip failure

Each time your computer is turned on, the system will check the  memory chips.  Occasionally one will fail.  If your machine passes the initial test, but DOS gives a memory  error while operating a program, you may be able to use diagnostic  software to find the problem.  These programs may be supplied by the  manufacturer of the machine, or are commercially available.

If your machine fails the initial test, you will not be able to  obtain the DOS prompt or see Windows start.  To repair memory problems, you will need to remove,  and test all chips with a special tool, or replace each chip and try  to reboot the machine.

Chips are located on strips, called SIMMS.  The entire strip must be removed and replaced.  Although there are machines for testing chips, very few computer companies will have them available.

Power supply failure

Power supplies can fail.  This is most often caused by overheating,  or a major surge of voltage on your electrical circuits.  The power supply contains the cooling fan for the system.  It should  be cleaned out periodically.  Should dirt be allowed to accumulate  in the fan inlet, or if the computer cabinet holes are blocked, the  system will overheat.  This will add a strain to the power supply,  and it will eventually die.

Power supply repair calls for replacing the unit.  This is the most  economical fix, regardless of the problem.  When a power supply goes, it may also cause damage to other cards in

the system, including the mother board.  Since it supplies voltage  to the whole system, if a

regulator were to short, and the circuits  received 110 volts, instead of 5, they would become

crispy quite  quickly.  While this doesn't happen very often, it certainly could.

Keyboard failure

Keyboard contacts can fail, rendering them useless.  This will  always happen when you

spill drinks in the keyboard, or allow a lot  of dust to accumulate.  The better keyboards use

sealed switches  while the less expensive units use surface contacts.  The keyboard also has some controlling chips which may fail.  These  are usually soldered into the circuitry, and are not easily replaced.  Keyboards are usually replaced, rather than repaired.      

Monitor/video card failure

Monitors are like televisions.  The most common cause of trouble is  the power supply.  Once it starts providing irregular voltage, the  system shuts down.  The video tubes rarely fail in monitors. Consequently, it is a good  investment to have the monitor repaired should the screen become fuzzy, dark, or fail to display.

Video cards will fail more frequently than monitors.  If you are not sure where the problem lies, take the monitor to another computer.  If it works, then the video card is at fault.  The board itself may  not be plugged into the motherboard "bus" completely, or the  contacts may have oxidized.  A pencil erasure will clean the  contacts quickly.  Checking the board's seating is also a good idea.  Simply press down on the top left, and right corners, simultaneously.  Tilted boards (with the back up in the air) are not  making clean contact.

Motherboard failure

Sometimes one of the chips on the motherboard will fail.  There are  two types of service.  The "board level repair" facility takes out  the old motherboard, and puts a new one in its place.  The old one  is sent out to be rebuilt, and you pay a fixed charge for the  "swap."

Realistically, this is often more economical than the "chip  level repair" facility, because their is very little labor time.  The chip level repair person will find the defective part, and  replace it

alone.  This may take more labor time, plus the cost of  the part.  If your repairs are performed by the manufacturer, they will utilize  board swapping.  If the manufacturer is no longer in business, you  will need to find a chip level repairman.

Lost Data:

The most common problem with Hardware is the result of an operator  turning off the power

before fully exiting the program.  The Disk  Operating System (DOS) stores information in

memory, which is only  active when the power is turned on.  When time permits, this  information is then written back to the hard disk.  When someone  turns the power off before fully exiting the program, and waiting for  about 1 minute so DOS can perform its cleanup task, they will contaminate the data files.  This occurs because only part of the  information was saved to disk, and the rest was lost when the memory  was turned off with the power.  The lost material must be reentered  because the system has no information available to correct the  problem.

Common Problems With Networks

Network Connection Lost:

Sometimes the computer will display a message that it has lost its  network connection.  This can result from:  

•        The server has been turned off

•        The interface card in the server or workstation has gone bad

•        The cable is loose or damaged

•        The boot up disk is defective in the workstation

•        A computer virus

Check each of these items to see if they may have contributed to the  problem.  Once you find the difficulty, and resolve it, reboot your  entire network, starting with the main server.

Cannot log into the program from a workstation:

On most networks, the .EXE files must be marked Read Only.  This is  done using the DOS ATTRIBUTE command.  While in the program directory  (ie. \ASW5), type ATTRIB   +r   *.EXE  Some people find the message that another user is already logged in  with the name which has been assigned.  Each workstation should have  its own, unique, user name.  The password may be the same for all of  them.  If you get the error message, you may press the ESC key, and you will  be prompted for the password. However, you should be sure that no  other people are really using the same name because this can effect  the screen printing.  This is a normal occurance if an error message pops up, and then  dumps