UNIX System Administration Handbook - Evi Nemeth [442]
One way to reduce static on carpeted floors is to purchase a spray bottle at your local Wal-Mart and fill it with one part Downy fabric softener to 10 parts water. Spray this on the carpet (but not on computing equipment) once every month to keep static levels low. This procedure also leaves your office area with that all-important April-fresh scent.
Reseating boards
You can fix many hardware problems by simply powering down the equipment, reseating its interface cards (SCSI, Ethernet, etc.) and powering it back up. To reseat a card, pull it out from its “seat” (usually a high-density connector) and then reinstall it. If this works temporarily but the same problem comes back a week or a month later, the electrical contact between the card and the motherboard is probably poor.
If the card uses an edge connector, take it all the way out and clean the contacts with a pencil eraser. Don’t use an eraser that is old and hard. If your eraser doesn’t work well erasing pencil marks from paper, it won’t work well on electrical contacts either. Try to keep your fingers off the contacts. Just “erase” them with the pencil eraser (a mild abrasive), brush off the eraser droppings, and reinstall the card.
Some motherboards (especially those of the PC variety) still have socketed ICs, although this is increasingly rare. Over time, the connections in the sockets deteriorate, mostly because of vibrations from fans. You can press firmly on the top of the chips with your thumb (after you’ve donned a grounding strap, of course) to tuck them in.
24.4 MONITORS
The monitor is often the least reliable component of modern computer systems. Many monitors have brightness and convergence adjustments that are accessible only from the circuit board. Unfortunately, monitors often use internal charges of tens of thousands of volts that can persist long after the power has been disconnected. Because of the risk of electric shock, we recommend that you always have your monitors adjusted by a qualified technician. Do not attempt the job yourself.
24.5 MEMORY MODULES
Most of today’s hardware accepts memory in the form of SIMMs (Single Inline Memory Modules) or DIMMs (Dual Inline Memory Modules) rather than individual chips. These modules range in size from 256K to 512MB, all on one little card.
If you need to add memory to a workstation or server, you can usually order it from a third-party vendor and install it yourself. Don’t buy memory from workstation vendors; they will soak you ‘til you’re good and soggy.1
When adding memory, think big. The price of memory is continually decreasing, but so is the standard allotment of expansion slots on a typical motherboard.
If you install your own memory, keep these two rules in mind:
• Memory is more sensitive than anything else to static electricity. Make sure you’re well grounded before opening a baggie full of memory.
• The connector that’s used to attach the module to the motherboard varies from machine to machine. Most usually snap in easily enough, but you need a special tool to remove them once they’ve been installed. It’s always tempting to use a ballpoint pen or a paper clip to release the fasteners, but this approach often ends up damaging the connector.
Memory modules are frequently a candidate for the pencil eraser cleaning technology described earlier in this chapter.
24.6 PREVENTIVE MAINTENANCE
Some pieces of hardware have filters that must be regularly cleaned or changed. Clogged filters impede the flow of air and may result in overheating, a major cause of equipment failure. It’s important to keep the air vents on all equipment open and unobstructed. It is not uncommon to find books or newspapers lying on top of a computer’s