Source: Tom's Guide | Keywords: troubleshoot, upgrade, fix | Themes: Desktop Computers
7. Power Supply
Your computer, depending on the design of its power supply, has the right to expect a steady and reliable source of electricity in the range of 110 to 120 volts at 50 to 60 cycles per second. (Your power supply may also be able to work with foreign current sources of 240 volts.)
Modern machine power supplies are pretty good at dealing with current that dips slightly below that range momentarily or that surges a bit above the top end for a few milliseconds. Power supplies are not designed to work with long-term overvoltage or undervoltage situations, however. Severe spikes can pass through some power supplies and travel through the low-voltage DC lines to the chips. Long-term overvoltage conditions stress every motor and every chip in the computer.
Chronic undervoltage produces its own set of symptoms. A hard disk that is getting less than 12 volts, for example, may not come up to speed the first three times you turn on the computer in the morning. The fourth time, though, it may work fine and seem okay all day. Low voltage can also cause mysterious intermittent computer lockups. If you are constantly replacing parts, I suggest that you buy or borrow a voltmeter or other line voltage-testing device and plug it into your wall socket. If the meter reads outside the expected range (about 100 to 120 volts) for no good reason, call the electric company or an electrician.
What can cause power fluctuations? The reasons run from the ordinary — a brownout on the hottest day of the summer or power line interference by major appliances — to just plain bad electrical service. When an air conditioner or a refrigerator turns on, the draw caused by its motor may produce a momentary dip in the line voltage, followed by a spike as the power comes back up. Thunderstorms are also notorious for the voltage spikes that they cause.
A momentary dip in current can cause the voltage to drop so low that the memory chips start to forget things. When this happens, the computer locks up. Perhaps you didn’t see the lights brown out for an instant during the voltage drop. It doesn’t matter, because a voltage drop lasting only a thousandth of a second can lock up an older computer.
Similarly, a momentary voltage spike to the hard disk head may write gibberish in the middle of a file, or, much worse, to the boot sector or the FAT (file allocation table). You won’t notice this problem until you go back and try to read the file or boot from the hard disk. This is where routine use of disk maintenance programs can pay off. Run a disk utility such as Norton Utilities on a regular basis so it can catch and repair these problems. If the boot sector is trashed, these utilities may be able to repair the boot sector or help you recover the FAT and files.
Every system in any home or office should, at the very least, be plugged into a spike protector. These units, which sell for $10 to $50, are electronic sacrificial lambs. They are intended to blow a fuse or even blow up themselves to shut down the line to your computer if a dangerous spike is headed its way. A line conditioner is a device (priced less than $100) that boosts the power during momentary drops and acts as a surge protector as well.
Uninterruptible power supply (UPS) systems are electronic guarantors of a reliable source of power in brownouts, overvoltage situations, and even power failures. They generally include line-conditioning circuitry, as well as a large internal battery and a regulator. UPSs come in two designs: a standby style that includes a very fast switch that can jump into the fray to substitute battery power for line current in an emergency, and a true uninterruptible style that constantly feeds your computer from its battery at the same time that it uses line current to keep the battery charged. UPS systems sell for about $100 to $300 for units intended to work with single PCs.
In my very rural office, the electrical system is rather unreliable. Undervoltage is common, storms bring the occasional spike, and brief — and sometimes extended — outages pop up regularly. All of the computers in my office are plugged into uninterruptible power supply (UPS) boxes, and electric spike protectors or line conditioners protect every other major device. The UPSs protect from under- and overvoltage incidents and provide about 15 minutes of battery power in the case of a complete outage — enough time to conduct an orderly shutdown. I also have all of my major applications and programs, including my word processor, configured to automatically save files in progress every five minutes. This means that the most I could lose in the event of an unexpected shutdown (or system crash) is whatever work I have done in the last 4 minutes and 59 seconds.
After the power gets past the surge protector, line conditioner, or UPS, the computer’s power supply is in charge of converting AC to DC and stepping down the voltage. In general, power supplies are usually good for many years of use; the entire PC will typically be out of date before the supply will fail.
But power supplies can fail, especially if they are not well-protected from over- or undervoltage. They can also break down if the cooling fan does not work or if vents are blocked. Here are some signs of the failure of a power supply:
- A completely dead system with no cooling fans running on the power supply or elsewhere in the case
- Repeated failure of the system to bootup
- Unexpected rebooting or shutdown of an operating machine
- Repeated parity check or other memory errors
You can test the output of a power supply with a voltmeter. It does not make economic sense to repair a faulty power supply within your PC. Replacement units sell for about $30 to $100 and installation is simple. Be sure to match the same physical size and design; you can, though, increase the wattage of the replacement unit.
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Not bad, but I'll take a few exceptions:
1 - cleaning up and defragmenting your hard disk is Windows specific.
The Microsoft block allocator is brain dead, was made that way, and will remain so for as long as Diskeeper and Norton Systemworks create revenue: a Mac OS X, xBSD or Linux-based system doesn't need defragmentation(*), as it is done by the OS on every disk access. You can get efficient defragmentation by:
- disabling System Restore: it doesn't work very well anyway, is a virus nest, and eats up to 6 Gb on your hard disk.
- setting your swap file to a fixed size.
- disabling file system indexing.
- deleting DrWatson's log.
- running Ccleaner once in a while with most settings enabled: once you have applied hotfixes, you don't need the uninstall files anyway. You'll need to clean up IE7's and WMP's patches yourself though.
- make Pagedefrag run at every boot after 0 second wait: the first time it may take a while to run, but it'll keep the Registry and swap file in one piece.
(*)to be fair, such a system may still fragment if you fill up a partition with huge files when it is already more than 80% full - Windows will fragment any file if you get past 10% partition capacity. Some say it's a way to prevent data corruption, as usually adjacent sectors are more likely to get corrupted, but then if that's the case Windows doesn't fragment ENOUGH.
2 - a resident antivirus is a resource drain.
Using a limited user account, a well configured firewall (in software or hardware, preferably both), and scanning downloaded files before you run them (and not making use of MS Outlook Express, which runs files for you) will keep you safe enough.
Not using IE may help, too: Opera or Firefox can operate as pure user level processes. Firefox 3 will be able to notify antivirus when a file is downloaded (if it interacts well with ClamAV, you can dump Norton and forget about the yearly AV tax).
3 - power surge protection.
A sound advice. However, a beefy PSU that you change every 1-2 years and a good power surge preventer are, in my experience, less costly and more efficient than a pack of batteries you'll need to renew every year. A good PSU in great shape can handle brown-outs, especially if your system doesn't draw too much current, and a surge protector will cover the PSU's most damaging attack. Changing the PSU regularly ensures that its capacitors remain at peak efficiency, and that its voltage regulators work as required. It is also unsound to clean up a PSU (it's dangerous!), so getting a new one is the most efficient way to get a clean one. With Vista, no UPS lasts long enough to allow you to save your files and shut down a system cleanly.
Clutz. I eat and drink around mine everyday and I've never once spilled so much as a drop of milk.
Milk eh?
I'd suggest keeping your files on a NAS drive or USB external drive and formatting your MS OS every year.
Besides running a limited account try Virtual Machines for avoiding those pesky viruses