Question 1

Computer security basics: If you suspect a malware infection, which of the following system elements will typically not be infected directly by the virus code?

Accepted Answer

Introduction / Context: Classic computer viruses target executable code and boot processes. Understanding what they can and cannot infect helps triage incidents and choose the right remediation steps (e.g., boot sector repair, file disinfection, media scanning). Given Data / Assumptions: We are considering traditional virus behavior (file infectors, boot sector viruses). Media like floppy disks can carry boot sector and file-based malware. CMOS stores configuration (time/date, boot order) rather than executable code. Concept / Approach: Viruses replicate by attaching to executable code or modifying boot sectors. While malware can alter CMOS settings (e.g., change time or boot order) via BIOS calls, CMOS itself is not executable storage that gets “infected” with code. In contrast, program files and boot sectors are frequent infection targets, and removable media like floppy disks commonly spread such infections. Step-by-Step Solution: Identify typical infection vectors: program files and boot sectors.Recognize that CMOS is configuration data, not a virus host medium.Choose CMOS as the element not infected directly by virus code. Verification / Alternative check: Incident response playbooks focus on scanning file systems and boot areas, not on “disinfecting” CMOS. Clearing CMOS may undo malicious setting changes but is not disinfection of code. Why Other Options Are Wrong: Boot sector: Common target for boot viruses. Floppy disks: Spread both boot and file-based malware. Program files: Classic file-infector targets. None of the above: Incorrect because CMOS is the correct exception. Common Pitfalls: Confusing altered CMOS settings with infection; overlooking that firmware rootkits target flash ROM, not CMOS RAM. Final Answer: CMOS

Question 2

Interface standards: RS-232 (Recommended Standard 232) defines electrical and signaling characteristics for which common PC interface?

Accepted Answer

Introduction / Context: Many legacy peripherals communicated via standardized physical layers and signaling protocols. RS-232 is one of the most enduring standards, particularly in service, console access, and embedded applications. Given Data / Assumptions: We are focusing on the PC context (COM ports). RS-232 specifies voltage levels, signal functions, and connector pinouts commonly associated with serial links. Parallel and game ports use different standards. Concept / Approach: RS-232 defines asynchronous serial communication, historically mapped to COM1/COM2 and presented on DB-25 or DE-9 connectors. It specifies line voltages (e.g., ±3 V to ±15 V), signal names (TXD, RXD, RTS, CTS, etc.), and basic timing for serial data exchange. Parallel ports follow IEEE 1284, and game ports use analog joystick interfaces unrelated to RS-232. Step-by-Step Solution: Identify the standard: RS-232 corresponds to serial communication.Map to PC terminology: COM ports are serial ports.Select “Serial port” as the correct answer. Verification / Alternative check: Hardware manuals label DE-9 connectors as RS-232 serial ports; USB-serial adapters emulate RS-232 signaling for legacy equipment, confirming the association. Why Other Options Are Wrong: Parallel port: Uses a different standard (IEEE 1284). Game port: Analog interface unrelated to RS-232. All of the above / None of the above: Both incorrect given RS-232’s clear scope. Common Pitfalls: Confusing connector shape with protocol; assuming DB-25 always equals RS-232 (it was also used for parallel on some systems). Final Answer: Serial port

Question 3

PC keyboard troubleshooting at the hardware level A desktop PC shows intermittent keyboard lockups even after replacing the keyboard with a new unit. Which of the following is the LEAST likely root cause?

Accepted Answer

Introduction / Context: When a PC keyboard freezes intermittently, technicians must decide whether the fault lies with the peripheral or with internal system hardware. This question evaluates structured troubleshooting, probability reasoning, and knowledge of the keyboard signal path from the device to the motherboard controller. Given Data / Assumptions: The old keyboard was swapped for a known-good replacement. The symptom (intermittent lockup) persists with the new keyboard. No mention of liquid spills or obvious mechanical damage on the new unit. Standard desktop PC with PS/2 or USB interface. Concept / Approach: Root-cause analysis weighs likelihoods. If replacing the peripheral does not change the symptom, the failure is typically upstream: port connector, cabling, keyboard controller (on older systems the Super I/O), or wider motherboard issues such as power rails or ESD damage. The chance of two unrelated keyboards being bad in the same way at the same time is small compared to a persistent system-side fault. Step-by-Step Solution: Establish that the symptom remains after swapping the keyboard → peripheral is less likely.Inspect the keyboard port for bent pins, cracked solder joints, or debris → connector issues are plausible.Consider the keyboard controller (Super I/O) or USB controller and firmware → very plausible for intermittent faults.Consider motherboard-level faults (noise on 5 V, ground bounce, ESD/overcurrent history) → plausible.Conclude the least likely cause is “a second bad keyboard.” Verification / Alternative check: Test the same keyboard on another PC; test a known-good spare on the suspect PC; try a USB-to-PS/2 adapter or alternate port; check system logs for controller resets; run diagnostics from firmware or the OS. If problems follow the PC, not the keyboard, the system hardware is implicated. Why Other Options Are Wrong: Keyboard controller chip: common failure point causing intermittent lock or missed scans. Connector: bent pins or cracked joints frequently cause intermittent contact. Motherboard: power or ground issues can disrupt the entire input path. “None of the above” is incorrect because the least likely option truly is a second bad keyboard. Common Pitfalls: Assuming “new equals good” without testing on another system; overlooking port damage; forgetting firmware/BIOS settings that may disable legacy PS/2; ignoring ESD history. Final Answer: A second bad keyboard.

Question 4

AT/ATX power wiring color codes On common PC power supply motherboard connectors, the conductor at pin 1 is typically associated with which wire color(s)?

Accepted Answer

Introduction / Context: Technicians working with legacy AT and modern ATX supplies must recognize pin numbering and wire color conventions to avoid miswiring and diagnosis errors. Pin 1 identification varies between standards but is consistently tied to specific color codes. Given Data / Assumptions: Question references “PC power supplies” broadly, implying both historical AT (P8/P9) and ATX main-board connectors may be encountered. Color codes follow typical industry conventions (orange for +3.3 V on ATX; white historically used for −5 V on older harnesses). We focus on the wire typically present at the Pin 1 position on the main motherboard connector according to common pinout charts. Concept / Approach: On the 20-pin/24-pin ATX connector, Pin 1 is +3.3 V and uses the orange conductor. On certain legacy AT harnesses, pin 1 of a given block could use white for a negative rail. Because the stem asks “usually” and presents a pair, the safe, standards-aligned choice that includes the modern norm is “white or orange,” acknowledging both conventions across eras, with orange being the prevalent ATX case. Step-by-Step Solution: Identify the connector standard in most modern PCs → ATX: Pin 1 = +3.3 V (orange).Acknowledge legacy contexts where white (−5 V) appears on early connectors.Select the option that encompasses the typical colors associated with Pin 1 positions → “white or orange.” Verification / Alternative check: Consult motherboard manuals and ATX specification pinouts, which consistently show orange at Pin 1. Legacy references for AT P8/P9 illustrate white conductors on pin 1 positions in older designs. Why Other Options Are Wrong: “Blue or red” and “red or black” do not match the established Pin 1 on ATX. “Red or white” pairs a common +5 V (red) with an older negative rail color, but red is not the ATX Pin 1. Thus, “white or orange” best fits cross-generation expectations. Common Pitfalls: Assuming all connectors share the same orientation; ignoring keyed housings; mixing peripheral (Molex) color assumptions with motherboard connectors. Final Answer: white or orange.

Question 5

Networking media recognition for support staff Which Ethernet physical layer standard most commonly uses RJ-45 modular connectors?

Accepted Answer

Introduction / Context: Correctly identifying cabling and connectors is essential for network installation and troubleshooting. RJ-45 connectors are ubiquitous in copper Ethernet deployments across offices, data centers, and home networks. Given Data / Assumptions: RJ-45 refers to the 8P8C modular connector commonly used for twisted-pair Ethernet. Legacy coax and fiber standards use distinct connectors and media. We are mapping a connector type (RJ-45) to its corresponding media standard. Concept / Approach: 10Base-T, Fast Ethernet (100Base-TX), and Gigabit Ethernet (1000Base-T) all use UTP/STP twisted-pair cabling terminated by RJ-45 connectors. By contrast, 10Base2 uses BNC connectors on RG-58 coax; 10Base5 uses vampire taps/AUI; and 10Base-FL is fiber with ST/SC/LC connectors. Step-by-Step Solution: Identify the connector in the question: RJ-45 → copper twisted-pair.Match to the Ethernet family built for twisted-pair: 10Base-T (and successors).Select “10Base-T (twisted pair).” Verification / Alternative check: Vendor installation guides and the IEEE 802.3 standard confirm RJ-45 use in 10/100/1000Base-T implementations. Why Other Options Are Wrong: 10Base2 and 10Base5 are coaxial systems without RJ-45. 10Base-FL is fiber, also not RJ-45. Common Pitfalls: Assuming RJ-11 (phone) equals RJ-45; confusing twisted-pair copper with fiber optics; overlooking shielded RJ-45 variants which still indicate copper twisted pair. Final Answer: 10Base-T (twisted pair).

Question 6

Preventing data loss during power disturbances Which option best ensures short power interruptions do not corrupt data on a computer system?

Accepted Answer

Introduction / Context: Power quality issues—sags, surges, and brief outages—can crash systems and corrupt filesystems. Selecting the correct protection device is critical for business continuity and home users alike. Given Data / Assumptions: The objective is to bridge short interruptions and allow safe shutdown. Standard AC mains environment is assumed. Computer equipment includes storage devices sensitive to sudden power loss. Concept / Approach: A UPS provides battery-backed AC power for a limited period, absorbing sags and covering brief outages. Surge protectors clamp high-voltage transients but do not supply power during outages. Proper grounding is essential for safety and noise control but cannot maintain power in a blackout. Step-by-Step Solution: Define requirement: continue operation through short interruptions.Evaluate devices: only a UPS converts stored energy into usable AC power during outages.Choose UPS as the correct solution. Verification / Alternative check: Vendor specifications for line-interactive and online UPS systems show ride-through capabilities ranging from minutes to hours depending on load and battery capacity. Why Other Options Are Wrong: Grounding improves safety/EMI but not continuity. Surge protectors address spikes, not outages. The humorous option is irrelevant. “None of the above” is wrong because UPS is correct. Common Pitfalls: Assuming a surge strip prevents data loss during blackouts; undersizing UPS capacity; forgetting to install power management software for graceful shutdown. Final Answer: UPS (Uninterruptible Power Supply).

Question 7

Field Replaceable Units (FRUs) in desktop support Which of the following is NOT typically considered a Field Replaceable Unit (FRU) in standard PC service practice?

Accepted Answer

Introduction / Context: FRUs are components that a technician is expected to replace on site without specialized rework equipment. Understanding what counts as a FRU helps plan spares and set realistic SLAs for field service. Given Data / Assumptions: Standard desktop PC environment is assumed. Common FRUs include PSU, drives, add-in cards, memory, and sometimes socketed ROM chips. Chassis replacement typically implies depot-level service or a rebuild, not a simple field swap. Concept / Approach: A FRU is modular, accessible, and replaceable with minimal disassembly. Power supplies and add-in video cards clearly qualify. Many systems have socketed firmware ROMs that can be swapped in the field per vendor procedure. The system chassis, however, is the structural enclosure and not generally stocked or replaced onsite; moving to a new chassis is effectively a re-build. Step-by-Step Solution: List clearly modular parts → PSU, cards, drives, DIMMs, sometimes BIOS ROM.Evaluate chassis → replacement requires full system transplant and is not typical field practice.Select “System chassis” as the non-FRU. Verification / Alternative check: OEM service manuals enumerate FRUs; chassis rarely appears except as a base assembly tied to depot service or complete system replacement. Why Other Options Are Wrong: System ROM may be a socketed chip or a reflashable module and is often treatable as a FRU. Power supplies and video controllers are prototypical FRUs. Common Pitfalls: Confusing “user-replaceable” with “field-replaceable”; assuming any part can be replaced onsite regardless of time and risk; overlooking ESD procedures. Final Answer: System chassis.

Question 8

Choosing an interface for an external CD-ROM drive (legacy PCs) Which controller standard natively supports connecting an external CD-ROM drive?

Accepted Answer

Introduction / Context: Before USB became universal, external optical drives commonly used SCSI. Knowing which legacy interfaces supported external devices helps with maintaining older workstations and lab equipment. Given Data / Assumptions: We consider classic PC storage interfaces: MFM, ESDI, and SCSI. Goal is to connect an external (out-of-chassis) CD-ROM unit. SCSI supports daisy-chaining and defined external cabling/terminations. Concept / Approach: MFM and ESDI are internal HDD interfaces with ribbon cables and no standardized external cabling for removable optical drives. SCSI, by design, supports multiple internal and external devices, using external connectors (e.g., Centronics, DB-25, HD-50, VHDCI) and termination rules. Many professional external CD-ROM and CD-R units shipped with SCSI. Step-by-Step Solution: Identify external connectivity requirement.Map to interface standards → only SCSI provides external device support.Select “SCSI.” Verification / Alternative check: Vendor datasheets for classic external CD-ROMs cite SCSI IDs, termination switches, and external connectors—confirming SCSI as the intended interface. Why Other Options Are Wrong: MFM and ESDI target internal drives; ARLL is not a standard external optical interface. “None of the above” fails because SCSI is correct. Common Pitfalls: Confusing SCSI with parallel-port adapters (which were slower and used different protocols); forgetting to set SCSI IDs and termination on a chain. Final Answer: SCSI.

Question 9

Basic electronics for PC repair Which electronic component primarily stores electric charge and can release it when needed in a circuit?

Accepted Answer

Introduction / Context: Understanding passive components is essential for diagnosing power supplies, motherboards, and peripheral electronics. Capacitors are everywhere—smoothing DC rails, decoupling noise, and timing in analog sections. Given Data / Assumptions: We focus on basic component functions, not specialized variants. “Stores electrical charge” refers to energy storage in an electric field between plates. Common capacitor types include electrolytic, ceramic, film, and tantalum. Concept / Approach: A capacitor stores energy according to E = 0.5 * C * V^2, where C is capacitance and V is voltage. In PCs, bulk electrolytics stabilize the 12 V/5 V/3.3 V rails; small ceramics provide local decoupling near ICs to shunt high-frequency noise to ground, improving signal integrity and power stability. Step-by-Step Solution: Identify the function in question: storing electric charge.Map to device physics: capacitor stores charge on plates separated by a dielectric.Select “capacitor.” Verification / Alternative check: Visual inspection of PCBs shows many capacitors near voltage regulators and CPU sockets, corroborating their role in charge storage and filtering. Why Other Options Are Wrong: Diode/rectifier control current direction; resistor dissipates energy as heat and limits current; transistor provides amplification/switching but is not a primary charge storage element. Common Pitfalls: Confusing batteries (chemical storage) with capacitors (electrostatic storage); assuming only electrolytics “store charge” while all capacitors do so by definition. Final Answer: capacitor.

Question 10

Laser printer imaging steps In the six-stage electrophotographic process, which step occurs between the conditioning (charging) phase and the developing phase?

Accepted Answer

Introduction / Context: Laser printers form images through a repeatable sequence: processing, charging, exposing, developing, transferring, fusing, and cleaning. Knowing the order helps isolate faults like faint print, ghosting, or backgrounding. Given Data / Assumptions: We refer to the canonical electrophotographic cycle used in most laser printers. “Conditioning” means uniformly charging the drum via the primary charge roller or corona. “Developing” means applying toner to the latent image on the drum. Concept / Approach: After the drum is uniformly charged, the laser (or LED array) selectively discharges regions to form an electrostatic latent image—this is the writing/exposure phase. Only then can toner be attracted to the discharged areas during development, making the visible toner image that will later be transferred to paper and fused by heat and pressure. Step-by-Step Solution: Conditioning: drum surface gets uniform charge.Writing/Exposure: laser scans and discharges image areas.Developing: toner adheres to the latent pattern.Therefore, the step between conditioning and developing is writing/exposure. Verification / Alternative check: Service manuals detail the sequence and provide tests (diagnostic prints) to isolate which stage is failing based on symptom patterns. Why Other Options Are Wrong: Transfer and fusing occur after development. Cleaning follows fusing to remove residual toner. “All of the above” cannot be correct because the sequence is ordered. Common Pitfalls: Confusing “developing” with “writing”; assuming the laser adds toner directly rather than creating a charge pattern first. Final Answer: Writing (exposure) phase.

Computer Hardware Questions