Here's an example of what I mean. My daughter called me at work, frustrated and upset. The DVD drive that she got for a birthday present wasn't working. After playing 20 questions about the drive, my daughter -- not yet a geek and very frustrated -- asked, "Where's the screwdriver?"
Another time her computer failed to power up. She diagnosed a bad power supply and replaced it, but when I got home, she still had the same problem. I started looking at it. I disconnected the ATX connector from the motherboard and connected it to a power supply tester. No power. I checked the AC line. When I moved the plug in the UPS power strip, bingo! There was an oxide/corrosion buildup on the plug/receptacle that was blocking power. Pull, plug, power, and the tester chirped approval. My daughter was upset -- she had to switch the power supplies back.
So what toys, er, tools do I have in my bag? Here's a list of some of my favorites, including estimated cost and description.
AC line monitor
Manufacturer: P3 International
Cost: About $30
This lets you see current AC line voltage, line frequency (are you really getting 60 cycles?), and the VA rating of connected equipment (computer, monitor, etc.) for that UPS purchase. It also shows the power factor of motorized equipment and will monitor usage over time.
Manufacturer: Soyo Computers
Function: From the Web site: "This debugging card will assist any technicians (from novice to advance users) in accurately and conveniently locating their hardware problems faster, cutting down the troubleshooting time drastically simply by displaying an easy to follow POST (Power On Self Test) code on its display."
Requirements: Any motherboard with an open PCI slot.
Cost: Roughly $50
Description: The first time I used this was at an InstallFest. A customer brought in a computer to be converted to Linux, but it wouldn't boot. I used this to check his computer. Result: Dead/failing motherboard. Saved him a shop trip and improved our "customer relations"!
Name: Wal-Mart "Winchester" (look in the fishing gear)
Cost: About $6
Description: Uses three AAA batteries to drive a white LED. Long reach, bright. Great for looking at gear in dark areas.
Cost: About $5
Description: One of those three-neon-bulb indicators to identify AC wiring problems. When used with a splitter, helps identify runtime problems (floating grounds) or power weirdness.
Cost: About $11
Description: Neat ratchet tool with blade, Phillips, Torx, and an assortment of sockets (English, not metric). Comes with bit holders that can fit in to an opening in the handle (I keep the blade and Phillips bits here). Also has an extendable magnet tip for picking up those nasty screws that fall into the cabinet or equipment areas.
Power supply tester
Cost: About $30
Description: I found this at Discount Electronics. Tests ATX, HDD, diskette, SATA power supply. Provides a handy beep for ATX testing to confirm the power-good signal.
Cost: About $5
Description: Small basic function. I use this to check analog voltages. Good for checking analog ranges within about 1/2 volt (depending on scale and accuracy). Can also check signal switching, lines engaging, lines disengaging, signal voltages switching (from card readers, for instance), and RS-232 signaling.
Cost: About $10
Description: I use this to check voltages, continuity, resistance. Also for checking batteries. Good for testing voltages to 1/10 volt.