Chapter 4 - Form Factors, Power Supplies, and Working Inside a Computer


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How many pins does the P1 connector have that use the ATX Version 2.2 standard? 24.
What are the maximum dimensions for a motherboard that uses the MicroATX form factor? Up to 9.6 x 9.6 inches.
Which form factor is a smaller version of the MicroATX form factor? Mini-ITX, designed for small systems such a home theater.
Which form factor used a riser card on the edge of the motherboard? The NLX (New Low-profile Extended) has only one expansion slot for a ‘bus riser’ or ‘daughter card’.
How many pins does the main power connector on a BTX motherboard have? 24, with the same pin out as the ATX 24 pin connector.
Which type of case form factor is best for keeping a system cool? BTX.
Which type of computer case is most popular for desktop systems? Slimline desktop.
What is the normal voltage of house electricity in the United States? 110 to 115 V AC.
Hot wires in home wiring are normally colored ____ and ground wires in computers are normally colored ____ . black, black.
What is the difference between a transformer and a rectifier? Which are found in a PC power supply? A transformer steps voltage down, and a rectifier turns AC current into DC current. Both.
What are the five voltages that can be produced by an ATX or BTX power supply? Which voltage is seldom used? 12, -12, 5, -5, and 3.3 volts DC. -5 volt DC.
What device uses the 12 V 6-pin power connector? High-end video cards using PCIe x16 slots. Version 1 uses the 6-pin connector and version 2 uses the 6-pin connector with an added 2-pin 12 V connector.
What device uses the 12 V 8-pin power connector? The processor as auxiliary power, on older main boards that do not use the 4-pin connector.
What is the purpose of the 4-pin auxiliary connector on a motherboard? 12 V auxiliary power for the processor.
What is the purpose of the 4-pin Molex connector? Power for IDE drives.
How do you determine the wattage capacity needed by a power supply? Add up the wattage of all of the components of the system and add 30%.
Which one component in a high-end gaming computer is likely to draw the most power? The video card.
Why is a power supply dangerous even after the power is disconnected? Because it may have high voltage stored in capacitors.
Which tool of a PC support technician is the most important tool to protect the system against ESD? A wrist strap.
Which permanently damages a computer component, damage caused by ESD or damage caused by EMI? ESD (Electrictostatic Discharge): as little as 10 volts may cause 1) catastrophic or 2) upset (intermittent) failure.
What is a simple way to detect EMI? Use an AM radio turned all the way down and listen.
What is an unintended, high-current, closed connection between two points in a circuit called? A short circuit.
What device protects a system against lightning strikes but does not protect against sags and brownouts? A surge protector.
What device protects a system against blackouts? A UPS (Uninterruptible Power Supply).
What two measurements are used to rate the capacity of a UPS? Clamping voltage and joules.
What unit of measure is used to describe the amount of work a surge suppressor can do before it stops protecting the circuit from an electrical surge? Joules.
Why is it important to have an indicator light on a surge suppressor? To indicate if the suppression feature is still working.
What are the two main types of uninterruptible power supplies? Common and SMART (also called intelligent UPS).
How does a smart UPS differ from one that is not smart? A smart UPS can be controlled by software from a computer.
What is the purpose of a POST diagnostic card? To enable a POST (Power On Self Test) that performs a series of tests when a computer is first turned on.
When taking a computer apart, why is it important to not stack boards on top of each other? Chips could be damaged this way.
When assembling a system, which do you install first, the drives or the motherboard? The main board.
List four computer symptoms that indicate a faulty power supply. The keyboard stops working at odd times. The main board fails or is damaged. The power supply overheats and becomes hot to the touch. Memory errors appear intermittently.