Safe Working Practices
The first consideration should be electrical safety:
- Switch off all power before removing or assembling any part of the computer.
- Wherever possible, remove power by unplugging the power cable; an on/off switch may be faulty and can be inadvertently switched on.
- Wear an anti-static wrist band or some other precaution to prevent any chips or circuits getting a potentially fatal shock from you or the tools you are using.
If you must work on equipment that has live electrical circuits, you should observe the following precautions:
- Do not work alone. Make sure that the person with you knows how to switch off the power if necessary.
- Remove all jewellery, metal-framed spectacles and other metal objects.
- Use insulated equipment where the insulation is in good condition.
As far as General Safety is concerned:
- Do not wear loose clothing when operating equipment with moving parts, such as printers and disk drives. Tie back long hair and remove or clip ties. Fasten or roll up loose sleeves.
- Take care when lifting heavy equipment. Lift by pushing with your leg muscles to reduce strain to the back. Do not lift equipment on your own if you suspect that it will be heavy for you.
- Keep your work area tidy and free from hazards such as moisture and trailing cables.
- After completing maintenance work, ensure that all safety devices are correctly reinstalled. Such devices include machine covers, shields, warning labels and ground wires.
Determining the PC's Configuration
Before you attempt to perform any maintenance on a PC it is wise to find out what you currently have installed in terms of monitor adapter, memory, disk drives etc. There are several methods for doing this as follows:
- For ISA machines use the Hardware configuration program which is part of your PCs BIOS. You can normally enter the configuration program when the PC is switched on (but before DOS starts) with a key stroke - typically the Delete key. However, the exact key stroke depends upon your BIOS manufacturer. For example, an Elonex PC with a BIOS written by Microid Research uses the Esc key. Check your PC documentation to find out how to get into your PC BIOS.
- For EISA or MCA machines you will need the reference or setup floppy disk that came supplied with the machine. Boot up from this disk and follow the menus.
- For any machine. You can run certain utilities which can report what your current hardware configuration is. Examples of these are Checkit from Touchstone software, and MSD which comes supplied as part of DOS from version 5 onwards .
- Open up the case and have a look!
CheckIt
Tools Required
Unless you are working on a PS/2 machine, in which case you will be able to take the machine completely to pieces with your bare hands, you will need a basic toolkit. This should consist of the following:
- A small flat bladed screwdriver
- A couple of Phillips screwdrivers
- A Torx driver (if working on Compaq machines)
- Tweezers
- Chip removers
- A tube for keeping loose screws safe
- Anti-static wrist band
- Anti-static bags
- Compressed air can, or PC Vacuum cleaner, or natural bristle brush
- Small torch
- Spare 3.5 inch floppy disks for backup (a tape streamer is better if possible)
- Useful utilities (Virus checkers, different version of DOS boot disks, CHECKIT, NORTON Utilities or similar)
Before You Begin Dismantling the PC
Some set-up configurations and fault finding activities require your full attention. To ensure you get it right observe the following:
- Make sure that you have all the relevant tools to hand
- Ensure you are working in as clean an environment as possible
- Try to take the PC away from the users' workplace so you are working under the minimum amount of pressure and interference.
- Remember - a rushed job is a botched job and will cost you more in time in the future
General Maintenance
If you have a PC opened up in front of you, perhaps to install a network card or memory, it may be worth performing some routine maintenance tasks that could prolong the lifespan of the PC.
Cleaning
A build up of dust can occur on the motherboard, this causes excessive heating and possible shorting.
Chip Seating
Give any socketed chips a firm press to make sure they are seated correctly. "Thermal creep" can cause this (chips working themselves loose due to expansion and contraction caused by heating/cooling.)
Visual Check
Make sure that chips are not displaying signs of overheating (discolouring or cracking) as this may be symptomatic of something fairly serious. Check that the capacitors are not overheating: they should all be about the same colour.
