A+ 220-1101 CompTIA Study Notes

A PSU (power supply unit) is a component that converts the AC power from the wall outlet into DC power that the PC components can use. A faulty or failing PSU can cause random system crashes, as well as other problems such as noise, overheating, or no power at all. A PSU can fail due to various reasons, such as age, dust, power surges, or poor quality.

To troubleshoot a PSU, the technician can use a multimeter to measure the voltage output of the PSU connectors. The voltage should be within the acceptable range of the specifications. For example, the 12V rail should be between 11.4V and 12.6V. If the voltage is too low or too high, the PSU is likely defective and needs to be replaced.

Alternatively, the technician can try swapping the PSU with a known good one and see if the system crashes persist. If the system works fine with a different PSU, then the original PSU is the problem and should be replaced.

The other options are not likely to fix the random system crashes. Testing the fan speed may help to diagnose overheating issues, but it is not related to the PSU. Disabling the USB ports may help to eliminate potential conflicts with USB devices, but it is not related to the PSU. Decreasing the RAM timings may help to improve performance and stability, but it is not related to the PSU.

References:

Fix Random PC Crashes: 10 Steps to Identify and Fix Issues

Why Does Windows Crash? The 9 Most Common Reasons

The correct answer is A. OLED.

OLED stands for Organic Light-emitting Diode, and it is one of the three display types available for laptops, along with TN (Twisted Nematic) and IPS (In-Plane Switching) panels1. OLED displays use organic compounds that emit light when an electric current is applied, unlike LCD displays that use a backlight to illuminate the pixels. OLED displays have several advantages over LCD displays, such as higher contrast, wider viewing angles, faster response times, and lower power consumption2. However, OLED displays are also more expensive, less common, and more prone to burn-in than LCD displays2.

CRT (Cathode Ray Tube), DLP (Digital Light Processing), and Plasma are not display types for laptops. CRT is an old technology that uses a vacuum tube to project an image on a phosphor screen. CRT monitors are bulky, heavy, and consume a lot of power3. DLP is a technology that uses a digital micromirror device and a light source to project an image on a screen or a wall. DLP is mainly used for projectors, not laptops4. Plasma is a technology that uses gas-filled cells that emit light when an electric current is applied. Plasma displays are mainly used for large-screen TVs, not laptops.

References:

1: Laptop Display 101: Display Types (TN, IPS, or OLED)

2: OLED vs LCD: which screen tech should you choose for your next laptop? | TechRadar

3: What is a CRT Monitor? - Definition from Techopedia

4: What is DLP (Digital Light Processing)? - Definition from WhatIs.com

What is plasma display? - Definition from WhatIs.com

AAA stands for Authentication, Authorization, and Accounting, and it is a framework that provides security services for network access control. Authentication verifies the identity of a user or device that requests access to a network resource. Authorization determines what level of access or privileges are granted to a user or device based on their identity or role. Accounting tracks and records the usage of network resources by users or devices for billing or auditing purposes. RADIUS (Remote Authentication Dial-In User Service) is a protocol that implements AAA functions by communicating with a central server that stores user credentials and policies.