- By Cheryl Schmidt
- May 24, 2013
This chapter is from the book
- Wearing a wrist strap or staying in contact with unpainted metal keeps you and the computing device at the same electrical potential so you won’t induce current into any part and weaken/damage it.
- EMI and RFI cause issues. Move the computer or the offending device and replace all slot covers/openings.
- When removing parts, have the right tools, lighting, antistatic items, and ample work space. Take notes. Don’t use magnetized tools. Avoid jarring hard drives.
- Be careful installing an I/O shield and be aware of standoffs when dealing with the motherboard.
- Laptops and mobile devices frequently have compartments for memory and expansion card. These devices frequently have plastic parts that must be removed. A scribe helps with prying plastics and covers off. Laptop speakers and DC power plug frequently have cables that run along the back or sides of the device. Keep screws separated and take notes for any parts removal.
- Ribbon cables have a colored stripe indicating pin 1. Pin 1 of a cable must attach to pin 1 of a connector.
- Preventive maintenance procedures prolong the life of the computer. Vacuum before spraying compressed air.
- An MSDS describes disposal and storage procedures and contains information about toxicity and health concerns. Cities/states have specific disposal rules for chemicals, batteries, CRTs, electronics, and so on. Always know the disposal rules in the area where you work.
- AC power goes into the power supply or mobile device power brick. DC power is provided to all internal parts of the computing device. AC and DC voltage checks can be done and only with DC power does polarity matter. Use the highest meter setting possible with unknown voltage levels. Power is measured in watts.
- Continuity checks are done on cabling and a good wire shows close to 0 ohms.
- A power supply converts AC to DC, distributes DC throughout a unit, and provides cooling. The power supply must be the correct form factor and able to supply the current amount of wattage for a particular voltage level such as +5V or +12V. Multiple “rails” are commonly available for +12V since the CPU commonly needs its own connection. The number and type of connectors vary, but converters can be purchased.
- Li-ion batteries are used with mobile devices. If a device must be attached to AC power or a USB port to work, replace the battery with one of with the correct DC power jack, appropriate DC voltage level, and current (amperage) equal to or higher than the original power brick.
- Conserve mobile device power by adding more RAM, turning off wireless/Bluetooth, configuring power options, reducing screen brightness, and avoiding temperature extremes.
- You use ACPI to control power options through BIOS and the operating system. Wake on LAN and Wake on Ring are power features that allow a device to be powered up from a lowered power condition for a specific purpose.
- An AC circuit tester, multimeter, and power supply tester are tools used with power problems.
- Power issues include overvoltage conditions such as a surge or spike that can be helped with surge protectors, power conditioners, and UPSs. Power conditioners and UPSs help with undervoltage conditions such as a sag. A UPS is the only device that powers a computer when a blackout occurs.
- Ensure that a surge protector has a Class A rating and adheres to the UL 1449 standard.
- Ensure that a UPS outputs a sine wave from the battery and can output enough power for attached devices.
- Have a Type C or Type A-B-C fire extinguisher around in case of fire.
- In all communications and written documentation, be professional and effective. Use proper capitalization, grammar, punctuation, and spelling.