Explain what you did, what you expected, and what happened instead
Is something completely missing? Partially missing? Intermittently missing? Is something added (noise)?
Minimum Working Example
“Find something and read it”
Pay attention to error messages and printed labels
Consult the manufacturer’s documentation
Search the web (use terms from your succinct problem definition)
Asking others
Put in the work yourself first, lest you annoy those you ask
Use your succinct problem definition
Provide your minimum working example
Potential sources of help:
Knowledgeable people you know
Internet discussion forums
Manufacturer technical support
Professional repair companies, preferably recommended by the manufacturer
CAUTIONS
If disconnecting something in an audio signal path, ensure its channel is muted or the power amps that channel feeds are turned off. Otherwise, you will hear loud pops as you unplug and plug in the connector. Be mindful of multiple outputs in the signal path, e.g., mains and monitors.
Don’t touch lamps/bulbs in lighting instruments, projectors, etc. The oils in your skin will make it heat or cool unevenly or excessively and shorten its life.
Allow projectors (and other equipment with lights and fans) to cool down before disconnecting power or you’ll shorten its lamp life. Power the device down, watch for indicator lights still on and fans still running. When the device is completely dark and silent, then it is safe to disconnect the power.
COMMON EQUIPMENT PROBLEMS AND SOLUTIONS
Unresponsive hardware
Correct inputs and outputs used?
Correct mode activated?
Error messages or warning lights?
No lights on the device lit: Power button? Burned out fuse in device (it will look like a burned out lamp)? Fuse in power strip? Tripped GFCI? Tripped circuit breaker? A receptacle tester will indicate active power to outlets as well as proper wiring and grounding (click here to read more).
Cables and connections
No connection: Use a continuity tester (or the resistance/Ohms setting on a multimeter) to look for broken conductors or shorts between conductors (click here to read more).
Partial connection:
Some analog video signals have separate conductors for red/green/blue or for brightness/hue, so a broken conductor may result in missing color information instead of a black screen.
Weak audio with changed balance between instruments can result from stereo phone plugs that aren’t plugged in all the way. This is because the tip (left signal) is touching the right input contact (which should be touching the ring of the plug) and the ring is touching the ground contact (introducing an inverted version of the right channel to be mixed with the left channel). Any instrument that is the same in both channels will be cancelled out; any instrument that is partially in both channels will be weakened. A similar but less dramatic effect can occur when the left and right speakers are wired “out of phase,” meaning the hot and ground conductors are reversed in one speaker.
Intermittent connection: irregular crackling audio, disrupted video signal, or sporadic unresponsiveness. A conductor is partially broken in some place. Wiggle cables and use a continuity tester to find it.
Ground loop: when electrically connected devices have multiple paths to ground (usually when they use outlets that go to different circuit breakers) it can hum in audio at 60Hz (with harmonics, so it’s hard to filter out) or horizontal lines in video. Some devices have a switch that will “lift” (disconnect) the ground at one end of the signal path. Be sure that all equipment is still properly grounded even when this is activated. To lift the ground in power cables, a cheater plug may be tempting to use, but it is not safe unless all equipment has one proper path to ground (click here to read more). An isolation transformer inserted in the signal path designed for audio or video signals is an appropriate tool (click here to read more).
EMI or RFI (electromagnetic interference or radio frequency interference): Electromagnetic fluctuations from nearby power cables, power transformers, arc lamps (e.g., fluorescent lights and CFLs), motors, and even radio stations can induce noise in cables. The result may sound/look like ground loops (see above), whines or static (sometimes voices in the case of radio reception), and it may interfere with control signals. An RF choke can be attached around a cable to block interference (click here to read more).
Long cable runs: These have more surface area exposed to interference sources (see above), but every signal will lose energy over a long run, resulting in quiet audio with less high frequencies, darker video, or unresponsive controllers. Sometimes amplifiers (whether manual or automatic) may try to compensate for the signal loss, resulting in more noise introduced into an audio or video signal, because the noise floor of the equipment and any interference is being amplified along with the weak signal.
Feedback: When any input device picks up the output it is feeding, the signal will reinforce itself and grow out of control. A microphone placed too close to a speaker or in its path will usually evoke a sinusoid Larsen tone. A camera that can see its own output on a projection screen or display will get brighter until it clips.
Electrical fire: Cut the power first. Dousing it may cause more damage and electrocution. Not all fire extinguishers are rated for electrical fires. Once the power is disconnected, it can be treated as an ordinary fire.
COMPUTERS
Overloaded CPU: If the computer is overloaded, audio may suffer brief isolated clicks or drop-outs or stutter. Video may suffer “dropped” frames (meaning temporarily frozen images) or blocky patches or deformed motion if a codec lowers image quality to maintain frame rate or if it misses encoding information (click here to read more).
Exit/Quit all unneeded programs, e.g., a weather update program, and turn off any processes that might run in the background during performance, e.g., software updates, virus scans.
If a program is unresponsive, use controls in the operating system to force quit the program (Ctrl-Alt-Del in Windows, Command-Option-Esc in Mac OS). Any unsaved data in the program will probably be lost.
If a device or multiple programs are malfunctioning, then warm reboot or soft rebootthe computer using the Restart function in the operating system (Ctrl-Alt-Del then click the Power icon and Restart in Windows; Select Restart from the Apple menu in the upper left corner of the screen in Mac OS).
If the operating system is unresponsive, first check that your controllers are plugged in properly. Then cold reboot or hard reboot it by holding the power button for 5–10 seconds until you hear the fans shut off (otherwise, the computer might just be in “sleep” mode). Then press the power button to boot it manually. Any unsaved data in the program will probably be lost and any open files might be corrupted.
In an emergency, e.g., to stop imminent damage to people or equipment, disconnecting the power cable may be necessary. In addition to losing any unsaved data and risking corrupted files, hardware in the computer or connected to it might be damaged.