repair tips & system hints

IDE seems to be going the way of the dodo bird. MFRs are dumping boxed drives on sale and IDE drives are fewer & fewer on the market.
external SATA RAID boxes are popular now.

There is a new case & (possibly new?) power supply spec: the DTX case.
this may necessitate a new power supply form factor as well. http://www.dtxpc.org/, http://en.wikipedia.org/wiki/Mini-DTX it is similar to the slimline desktops of old, but takes mini-ITX boards. Heat may be a consideration for DIYers if they choose the higher-end processor/board combinations. Mini-ITX boards are sometimes fanless (like the slower C3 & C7 processors) so these can be silent boxes, good for multimedia applications, but for doing video, you're going to want a higher-end processor/mb combo like a pentium4, and case fit is going to be interesting. A 2.5" laptop hard drive is often the dirve of choice for a DTX case.
Mini-ITX boards are sometimes mounted in cars using special fanless cases.
some people are fitting micro-ATX boards into DTX cases because some can take it.

according to http://en.wikipedia.org/wiki/ATX_power_supply gives reference to case styles.

Windows XP came up with a new kind of Peer-to-Peer TCP/IP networking that involves the SNMP protocol. ick. security hole. there is no documentation I can find on how it works or what ports it uses so you can control it at the router. :-(

Peer-to-peer networking between Windows 98/ME and Windows XP doesn't seem to work without NETBEUI installed. and *that* requires the XP Home/Pro installation cd. Who knows if Vista still has it or not. And you still have to make a network setup disk from the XP box for the 98/ME box. same goes for windows 2000.
If I remember right, Windows 2000 doesn't quite communicate directly with XP either. I think it was back to NETBEUI there too. then ip address connections worked. but I had problems with files or transfers over 64k in size at times.
in short, use the same OS, or get an FTP server like filezilla server, or set up your own limewire or bittorrent (ports 6881-6889 I think) client & lock down the ports at the router so it can't get out.
If you have ideas on making things work without 3rd party programs, please tell us. that would be most helpful in a networking section.

motherboard beep codes are being replaced by speech synthesizers. so I guess speakers are back in style instead of those piezo buzzers.

Oftentimes the PSU that comes with the case is not a good one. Do some research. Even within some MFRs some models will be better than others, like Antec's Neo-something-or-other: there was a certain model of this that goes gunnybags consistently.
With some video card like the 8800GTS, a single-rail 12V supply is required at 550W-600W because the card draws 26A and a dual-rail supply only supplies 19A on each rail. Most every MFR supplies dual-rail PSU's now. PC Power & Cooling is the exception for ATX form factor (actually, a number of their power supplies are about 2" longer). I do not know of any others. PCP&C also make replacement power supplies for certain Dell models, although Dell doesn't recommend upgrades.

some BIOSes such as the DELL bios, store a "bad" event log, such as loss of battery, keyboard errors, memory size change, and the like.
If the user hasn't cleared this, you can check this to see which events beyond the ones marked "acknowledged" are new, and get an idea what has happened with the system.

Upgrading and Repairing PC's, please update the power supply section regarding table 19.21 the information is old.
optical drives: on average, they use 1.2A@5V, 1.5A@12V (24W)
please include watts rating in the table. some people don't know how to calculate it.
I don't know what blu-ray drives use.
I don't know about other devices, but just look at some. try looking at the new 7k1000 1TB drive from Hitachi for instance it has packed more platters than any other 3.5" form-factor drive and generates a lot more heat, and it's a lot faster. here's a good maximum to look at for hard disks. it takes 13.6W during random access.
Hard disk, minimum: 0.5A@5V, 0.4A@12V (7.3W) this is a 20GB Fujitsu

all 7200rpm or drives over ~200GB drives now require a hard drive cooler. if one is not installed, chances are the drive will not survive long unless it has sufficient cooling via a good direct fan. simply mounting into a case is not sufficient anymore unless the bay has a fan forcing air down it. there are cases like that, such as the Antec P180/182/P190 series. I know of one person with a 300GB drive who had to send in his drive to a HD data recovery services shop because of what I determined to be stiction, where the drive gets so hot the lubricant on the platters of some drives become like glue - when the drive parks & cools, that's it - platter no move, and the drive makes a chirping sound while it tries to spin the platter and eventually gives up.
And it's hard to find good coolers - most often you're going to have to bend off some drive bay ears to mount most of the good ones that have 2 big fans. You have to decide whether the extra noise is worth your data or not.
some coolers are not rated for drives over 500GB. I looked at reviews for cooling factors since the ads didn't specify any - some are better than others and will cool 10 degrees C or so.

this is the same reason I don't recommend most external USB hard drives except for Apricorn, LaCie 2TB, Glyph, coolmax case, which has a fan. after 3 hours of continuous use during a system backup (which is what they are touted for), the drive may just die from overheat (drive light blinks at you like a beacon with a Maxtor). this is the test to see whether your model will stand up or not. rather expensive test.
Glyph is all metal, supposed to be a good drive, and appears to have a fan - high end. There are external USB cases like the coolmax from a few manufacturers that do have fans in them, but they are hard to find. performance-pcs.com has some and so does cyberguys.com (has one with internal 80mm fan but case is plastic rather than metal and fails prematurely). these are often rated for no more than 500GB.

The ATA/ATAPI/IDE standard says no cables longer than 18" (otherwide you get bluescreens, lockups, crashes, etc according to the author of Upgrading and Repairing PC's)

about cleaning cd lenses: I do NOT recommend mixing alcohol and cotton swabs. especially grocery-store-bought isopropyl alcohol. Even if it says 90% ISOPROPYL, what's the other 10%? The combination leaves a milky white film behind after it dries. yuck. I stopped cleaning disk drive heads with this when I noticed I had to wipe this white stuff off afterwards.
from any electronics store where they sell electronic parts & associated chemicals you can get foam-tipped cleaning swabs, such as those by chemtronics. 1-800-645-5244 you can probably find a distributor, such as digi-key.com.
An example is foamtips #140, 2.88" long.
They also sell repairman-grade tape-head cleaning alcohol (which contains some other fluoro chemicals).
For floppy drives, the best thing you can do is get one of those cleaning kits. the alcohol is good, and the cleaning disk, well, you don't have to pry the heads apart.

After about about 2 or 3 400-floppy backups (about 800-1200 floppy full-writes), floppy drive heads just wear out I've found, and no cleaning is going to fix it.

I've also had problems with house dust being the major reason for having the need to replace an optical drive on a regular basis. It just gummed up the works & ruined the drive. Cleaning the drive out and the heads did not work. A vaccuum cleaner is maybe good for the tool kit too if you're doing repair (good for vaccuuming toner).

beware of firewire drives and XP Sp2?