Question 1

Stale Directory Listings from a Floppy Drive  After changing diskettes, the system keeps showing the previous disk's directory. The drive tests fine in a known-good system. What should you replace next in the original system?

Accepted Answer

Introduction / Context: Legacy floppy subsystems rely on a disk-change signal to inform the operating system when media has been swapped. If that signal is not conveyed, the OS may continue to present cached directory entries from the prior diskette. Given Data / Assumptions: The suspect drive works normally in a test bench system. Only the original host system exhibits stale directory listings. Cable orientation and pin integrity are known issues in floppy setups (twist cable, pin 34 disk-change line). Concept / Approach: Because the drive itself is verified good, the fault likely lies in the cabling or motherboard connector that conveys the disk-change signal (commonly on pin 34). A damaged, mis-crimped, or incorrectly oriented ribbon cable can prevent the host from detecting a media change, causing persistent old directory data to be reported. Step-by-Step Solution: Inspect the floppy ribbon for damage, twists, and correct keyed orientation (red stripe to pin 1).Verify that pin 34 is continuous end-to-end with no breaks.Replace the ribbon cable with a known-good cable compatible with the system.Retest by swapping diskettes and issuing directory listings to confirm disk-change detection. Verification / Alternative check: After replacing the cable, the OS should properly detect new media and refresh the directory. If problems persist, test the motherboard floppy controller header or consider a controller add-in card. Why Other Options Are Wrong: Device driver: Unlikely if the same OS works with other drives; symptom matches a hardware signal path failure. IDE controller: Irrelevant; floppy drives are not on IDE. Power supply: Would cause broader instability, not a specific disk-change issue. None of the above: Incorrect because the cable is the most probable failure point here. Common Pitfalls: Reversing the cable; using a cable without the necessary twist; overlooking bent pins; assuming the drive is bad when the issue is signaling. Final Answer: Floppy drive ribbon cable

Question 2

Standard PC IRQ Usage  IRQ6 is typically reserved for which hardware device in classic PC architectures?

Accepted Answer

Introduction / Context: Interrupt Request Lines (IRQs) are used by devices to signal the CPU. Classic PC platforms assign standard IRQs to common peripherals, and knowing these defaults speeds up troubleshooting legacy hardware and embedded systems derived from PC designs. Given Data / Assumptions: Standard ISA-derived IRQ mapping. Legacy floppy disk controller present. PS/2 keyboard and serial/parallel devices use their traditional IRQs. Concept / Approach: In the classic mapping, IRQ6 is used by the floppy disk controller. This convention persists in many BIOS and service references. The keyboard controller uses IRQ1, typical parallel ports use IRQ5 or IRQ7, and modems often share IRQ3 or IRQ4 depending on COM port assignment. Step-by-Step Solution: Recall standard IRQ map: IRQ0 timer, IRQ1 keyboard, IRQ3/4 serial, IRQ5/7 parallel/sound, IRQ6 floppy.Match device functions with their IRQ line.Select the device historically mapped to IRQ6: the floppy controller. Verification / Alternative check: BIOS setup screens and service manuals list IRQ6 for the floppy controller. OS device managers from DOS/Windows era corroborate this default routing. Why Other Options Are Wrong: Keyboard controller: IRQ1 by default. LPT2: Commonly IRQ5 or IRQ7. Modem: Typically IRQ3 or IRQ4 associated with COM2/COM1, not IRQ6. None of the above: Incorrect because floppy is correct. Common Pitfalls: Assuming PnP/ACPI modern systems always follow ISA defaults; while abstracted today, historical mappings still appear in exam and repair contexts. Final Answer: The floppy

Question 3

XT-Class 8-bit ISA Bus: Number of IRQ Levels  How many standard interrupt levels are provided on the original 8-bit ISA bus (XT-class computer)?

Accepted Answer

Introduction / Context: Early IBM PC/XT systems used the 8-bit ISA bus with a single Programmable Interrupt Controller (PIC). Understanding the number of IRQ levels available clarifies device limitations and resource conflicts on vintage systems. Given Data / Assumptions: IBM PC/XT architecture with one 8259A PIC. No cascaded second PIC as in later AT-class systems. We are counting standard, usable IRQ lines. Concept / Approach: The XT-class machine provides 8 interrupt request lines, IRQ0 through IRQ7, managed by a single 8259A PIC. Later AT-class systems (16-bit ISA) added a second PIC cascaded on IRQ2, providing IRQ0–IRQ15. Therefore, the correct number for the 8-bit XT system is 8. Step-by-Step Solution: Identify platform: XT-class 8-bit ISA.Recall single 8259A PIC = 8 priority levels.Select 8 as the number of standard IRQ levels. Verification / Alternative check: Technical references list IRQ0–IRQ7 for XT, and IRQ0–IRQ15 for AT due to the cascaded PIC pair. This distinction is foundational in legacy PC hardware documentation. Why Other Options Are Wrong: 4: Too few; the PIC provides 8. 12 or 16: Reflect expanded systems (16 for AT), not XT. None of the above: Incorrect because 8 is correct. Common Pitfalls: Confusing XT and AT capabilities; forgetting that IRQ2 in AT is used for PIC cascade and remapped to IRQ9 for devices. Final Answer: 8

Question 4

Fire Safety for Electronics  What class of fire extinguisher should be used to safely extinguish an electrical (energized equipment) fire, such as a computer?

Accepted Answer

Introduction / Context: Electronics and computers are powered electrical equipment. Using the correct fire extinguisher class prevents electrical shock, equipment damage, and the spread of fire. Safety protocols require choosing extinguishing agents compatible with energized circuits. Given Data / Assumptions: The computer is still connected to power (energized). We are selecting the appropriate extinguisher class according to common standards. Water-based agents are dangerous on live electrical circuits. Concept / Approach: Class C fire extinguishers are designed for electrical fires involving energized equipment. They use non-conductive agents (such as CO2 or dry chemicals) to smother the fire while minimizing electrical conduction risk. Class A is for ordinary combustibles (wood, paper), and water hoses or foams can conduct electricity, increasing hazard. Step-by-Step Solution: Identify fire type: live electrical equipment (computer).Select the extinguisher class rated for electrical hazards: Class C.If safe, de-energize equipment first; then Class A/B agents may be applicable depending on remaining material fires.Maintain proper distance and follow PASS technique (Pull, Aim, Squeeze, Sweep). Verification / Alternative check: Safety training materials and extinguisher labeling confirm that Class C is intended for energized electrical equipment. CO2 and certain dry chemical extinguishers carry the Class C rating. Why Other Options Are Wrong: Fire hose / water foam: Potentially conductive; unsafe on live circuits. Class A: For ordinary combustibles, not energized equipment. None of the above: Incorrect because Class C is the correct, standard choice. Common Pitfalls: Attempting to use water; forgetting to cut power when possible; not checking extinguisher ratings; inadequate training leading to improper aiming or distance. Final Answer: Class C extinguisher

Question 5

PC Card (PCMCIA) form factors: A PCMCIA card measuring 10.5 mm in thickness belongs to which type classification?

Accepted Answer

Introduction / Context: Older laptops used PCMCIA (PC Card) slots that accepted several card thicknesses for modems, network adapters, flash storage, and miniature hard drives. Knowing the correct type prevents damage and ensures the right device is used in the correct bay. Given Data / Assumptions: The card thickness is specified as 10.5 mm. We are classifying the PCMCIA type by physical thickness only (not function). All types share the same edge connector but differ in mechanical height. Concept / Approach: PCMCIA defines three common card heights: Type I is 3.3 mm (usually memory), Type II is 5.0 mm (typical for modems and NICs), and Type III is 10.5 mm (accommodates miniature hard disk drives or devices needing more vertical clearance). Therefore, a 10.5 mm card corresponds to Type III. Step-by-Step Solution: Identify numerical thickness given: 10.5 mm.Recall PCMCIA thickness mapping: Type I = 3.3 mm, Type II = 5.0 mm, Type III = 10.5 mm.Match 10.5 mm to Type III.Select the option labeled 'type 3'. Verification / Alternative check: Service manuals often state that a Type III bay may occupy the space of two adjacent Type II slots; visual inspection shows a deeper cage for Type III devices such as PC Card hard drives. Why Other Options Are Wrong: Type 1 and Type 2 are too thin. 'Type 1 and 3' is not a single, valid classification. 'None of the above' is invalid because Type 3 is correct by standard definition. Common Pitfalls: Attempting to insert a Type III card into a laptop that only supports Type I/II can jam or damage the eject mechanism. Conversely, assuming electrical incompatibility when the issue is purely mechanical can lead to unnecessary replacement of functional cards. Final Answer: type 3

Question 6

PC won’t spin up an IDE/ATA hard drive at power-on: What is the most likely cause when the hard disk does not spin?

Accepted Answer

Introduction / Context: When a desktop IDE/ATA hard drive fails to spin at power-on, the fault is usually in the power path rather than the data path. Recognizing the most probable failure saves time during triage and reduces the risk of data loss. Given Data / Assumptions: Symptom: the drive does not spin (no vibration, no whine). Standard 4-pin peripheral power (Molex) connector is used. No prior indication of firmware or logical errors. Concept / Approach: Spinning the platters requires 12 V and 5 V from the PSU via the Molex connector. A loose or oxidized Molex connection is common and immediately prevents motor startup. By contrast, a bad data cable or wrong jumper affects detection and transfer but does not stop the motor from spinning. Viruses and system-board configuration do not physically inhibit the spindle motor at power-on. Step-by-Step Solution: Power off and reseat the 4-pin Molex firmly (do not rock by the wires).Inspect connector pins for backing-out or looseness; try a different PSU lead if available.Power on and check for spin-up; then proceed to jumpers and data cabling if still not spinning.If the drive remains silent, test in another PC to rule out PSU failure. Verification / Alternative check: Measuring voltage on the Molex (yellow ~12 V, red ~5 V, black grounds) confirms power presence. Observing in another system further isolates the fault to drive or PSU. Why Other Options Are Wrong: Bad data cable: the drive typically still spins. Incorrect jumper: affects master/slave detection, not motor power. Virus: cannot prevent motor spin at POST. 'tfad system board': not a meaningful diagnosis and unlikely compared to a simple loose power connector. Common Pitfalls: Forgetting that SATA/IDE drives can feel very quiet; always touch the drive frame to confirm vibration. Avoid hot-plugging Molex on non-hot-swap systems. Final Answer: loose Molex connector

Question 7

Laser printer service outcome: After servicing a laser printer, you observe dirty prints (residual toner smudges). Which action is most likely to clear the issue?

Accepted Answer

Introduction / Context: After maintenance (e.g., replacing a toner or servicing internal assemblies), residual loose toner can remain on internal paper paths or the drum/fuser area. A simple, controlled method typically removes residual toner without further disassembly. Given Data / Assumptions: Printer just serviced; now prints are dirty/smudged. No prior symptom of the same degree. Printer otherwise feeds paper and fuses normally. Concept / Approach: Running several blank pages helps the system self-clean by picking up loose toner left in the paper path, transfer area, and fuser entrance. Many service guides recommend printing 5–10 blank sheets after replacing consumables. Deep cleaning the developer tank or laser diode is rarely needed for a sudden post-service smudge unless a specific fault exists. Resetting the printer does nothing to remove physical toner. Step-by-Step Solution: Open and re-seat the toner and drum units properly.Print multiple blank pages to carry residual toner out.Inspect output; if smudges persist, check for damaged wiper blade or leaky cartridge.If needed, use approved lint-free cleaning methods on accessible paths. Verification / Alternative check: Observe the trend: if prints progressively clean up, residual toner was the cause. If the defect repeats in a periodic pattern, suspect a drum or fuser defect based on defect spacing. Why Other Options Are Wrong: Developer tank cleaning is model-specific and unnecessary in most cartridge-integrated systems. Printer reset does not address toner residue. Cleaning the laser diode is risky, rarely needed, and unrelated to random smudges. Common Pitfalls: Touching the drum surface with bare hands or using non-approved solvents can permanently damage the imaging unit. Final Answer: Run several blank pages

Question 8

Leased line troubleshooting: On a leased-line installation, a known-good external modem shows no Carrier Detect (CD) light. Where is the problem most likely located?

Accepted Answer

Introduction / Context: On dedicated (leased) data circuits, the Carrier Detect (CD) indicator reflects the presence of a valid carrier from the remote end or network equipment. Absence of CD on a known-good modem points away from the local DTE (computer) and toward the line or network side (DCE path). Given Data / Assumptions: The external modem is known good (recently tested elsewhere or loopback verified). Cabling between the modem and computer is correct. Only the CD indicator is off; power and other LEDs are nominal. Concept / Approach: CD depends on receiving carrier from the far end via the telco leased circuit or CSU/DSU path. If the modem is sound and cabling to the computer is fine, the likely fault is in the telco loop (wiring, provisioning, or remote equipment). While specific enterprise setups may route through DTC/CSU devices, the umbrella description 'phone line' here represents the leased circuit path under carrier control, which is the most common failure domain for no-carrier conditions. Step-by-Step Solution: Confirm local modem self-test and loopback pass.Check for dial tone or line voltage (as applicable) and correct line assignment.Escalate a line test to the provider if CD remains absent.Verify remote endpoint status once the carrier confirms circuit health. Verification / Alternative check: Perform a local analog/digital loopback; if CD appears in loopback but not on the live circuit, the telco path is implicated. Why Other Options Are Wrong: Modem failure is unlikely given 'known good'. The computer does not affect CD (it is a DTE signal). 'DTC equipment' is too specific and not generally implicated without evidence. Common Pitfalls: Swapping PC serial cables or COM settings when the issue is on the telco side; overlooking mis-provisioned circuits. Final Answer: In the phone line

Question 9

Graphics memory types: WRAM (Window RAM) is typically found on which computer component?

Accepted Answer

Introduction / Context: Specialized RAM types have been used to accelerate graphics operations. WRAM (Window RAM) is one such video-oriented memory technology that improved throughput for graphics windows and high-resolution displays, especially in earlier workstation and PC graphics boards. Given Data / Assumptions: WRAM refers to Window RAM, not wireless or write RAM. Question asks where WRAM is used as a component. Concept / Approach: WRAM is a dual-ported graphics memory used on video adapters. It enabled efficient block moves, windowing operations, and higher bandwidth to frame buffers compared to conventional DRAM of its era. Therefore, the logical location is the video card (graphics adapter). Step-by-Step Solution: Identify WRAM as graphics-specific RAM.Recall that it sits alongside the GPU/DAC on the adapter.Choose 'video card' as the host component. Verification / Alternative check: Historical specifications of graphics boards (e.g., Matrox, Tseng, and others) list WRAM capacities and bus widths paired with their chipsets. Why Other Options Are Wrong: Modems and ATA connectors do not host display frame buffers. Motherboards may have system RAM or integrated graphics, but the term WRAM refers to display memory used on the graphics subsystem rather than general motherboard memory. Common Pitfalls: Confusing WRAM with VRAM generically; while both are video memories, WRAM is a specific optimized implementation. Final Answer: video card

Question 10

Floppy subsystem error: What is the most likely cause of an 'FDD controller failure' message after installing a floppy disk drive?

Accepted Answer

Introduction / Context: Legacy floppy disk drives use a keyed ribbon cable with a twist designating drive A/B. Misorientation of the cable is a classic cause of boot-time controller errors and nonfunctional drive activity lights. Given Data / Assumptions: Recent installation of a floppy drive precedes the error. Message indicates controller-level problem at POST. Hardware is otherwise functioning. Concept / Approach: Reversing the 34-pin cable at the drive or motherboard confuses the controller signals and power to the drive select logic, resulting in 'FDD controller failure' or constant LED illumination. This is more common than actual controller or drive defects. Correct orientation aligns pin 1 (marked by a stripe) on both ends with pin 1 headers. Step-by-Step Solution: Power down and unplug the system.Verify the stripe (pin 1) aligns to pin 1 on both drive and motherboard headers.Ensure the twisted end of the cable is connected to the A: drive if two drives are present.Reboot and confirm POST passes without FDD errors. Verification / Alternative check: The drive LED stuck on at power-up strongly hints at a reversed cable. Correcting the orientation typically clears the fault instantly. Why Other Options Are Wrong: Floppy drives generally have no 'flash CMOS' requirement; CMOS flashing is unrelated. Jumper errors are rare on common 3.5-inch drives (cable twist selects A/B). Actual drive defects are less likely than a cabling mistake given the timing. Common Pitfalls: Forcing the connector on non-keyed headers; not recognizing pin 1 indicators on older boards. Final Answer: you installed the floppy disk drive cable backward

Question 11

Basic meter use: When testing a fuse with a Volt-Ohm meter (digital multimeter), which measurement setting should you use?

Accepted Answer

Introduction / Context: A fuse is a passive component intended to be either continuous (very low resistance) or open (infinite resistance). Selecting the proper multimeter function ensures a quick and safe continuity check without powering the circuit under test. Given Data / Assumptions: The fuse is removed from the circuit or the circuit is fully powered off. A standard digital multimeter with AC, DC, current, and resistance ranges is available. Concept / Approach: Continuity is determined using the resistance (ohms) function. A good fuse measures near 0 ohms (or beeps in continuity mode). Using AC or DC voltage ranges does not reveal continuity in an unpowered fuse. Current (amps) mode is dangerous if placed across a component because it effectively shorts the meter leads through the meter shunt. Step-by-Step Solution: Power the device off and, if possible, remove the fuse from its holder.Set the meter to OHMS or continuity.Touch probes to both ends of the fuse; observe a near-zero reading for a good fuse.If the reading is OL or very high, the fuse is blown. Verification / Alternative check: Use continuity tone if available; a steady tone indicates a good fuse. Visual inspection for a broken element can support the measurement but is not definitive. Why Other Options Are Wrong: AC and DC ranges read voltages, not continuity. AMPS range risks meter damage and blown meter fuse. Common Pitfalls: Testing in-circuit can produce misleading parallel paths; remove power and isolate the fuse when possible. Final Answer: OHMS

Question 12

Connector identification: You have a 15-pin female connector with the pins arranged in two rows. Which device would typically use this connector?

Accepted Answer

Introduction / Context: Correctly identifying legacy connectors is essential for supporting older PCs and peripherals. A 15-pin, two-row D-sub connector is a classic hallmark of the game/MIDI port found on many sound cards and older motherboards. Given Data / Assumptions: Connector: 15-pin female, two rows (DA-15F form factor). Context: legacy PC ports (pre-USB era) for joysticks and MIDI breakout cables. Concept / Approach: There are two common 15-pin connectors in PCs: DA-15 (two rows) and HD-15 (three rows). The DA-15 female is associated with the game/MIDI port used for analog joysticks (and via breakout, MIDI). The HD-15 female (three rows) is the VGA video connector. Therefore, a 15-pin, two-row female connector is for a joystick (game port). Step-by-Step Solution: Confirm pin count (15) and row count (2).Distinguish DA-15F (two rows) from HD-15F (three rows).Associate DA-15F with game/MIDI port on sound cards.Select 'Joystick' as the correct device. Verification / Alternative check: Photographs or port labeling (a small joystick icon) on bracket I/O shields confirm identification; breakout adapters label MIDI In/Out using the same port. Why Other Options Are Wrong: Serial devices use DE-9 or DB-25. Parallel devices use DB-25. MIDI devices alone do not mate directly with DA-15 without an adapter. Video devices (VGA) use HD-15 with three rows, not two. Common Pitfalls: Confusing the two-row DA-15 with the three-row HD-15; miscounting rows due to viewing angle. Final Answer: Joystick

Question 13

POST beeps absent: When a PC boots and no beep is heard from the chassis speaker, what is the most likely explanation?

Accepted Answer

Introduction / Context: Power-On Self-Test (POST) beeps provide audible diagnostics before video initializes. If no beeps are heard, it may indicate a fault or simply that the speaker is not functioning or not connected. Identifying the most probable cause guides efficient troubleshooting. Given Data / Assumptions: No beep at power-on under any condition. System otherwise powers (fans, LEDs). No assumption of motherboard-integrated speaker unless confirmed. Concept / Approach: Many modern boards omit a built-in buzzer; they rely on a small chassis speaker connected to front-panel headers. If that speaker is missing, faulty, or miswired, you will not hear any POST beep—even if the system is fine or even if it is signaling errors. Therefore, a bad or disconnected speaker is the most common reason for silence. Other listed causes are less directly related to the presence of a beep itself. Step-by-Step Solution: Inspect the speaker/buzzer header and verify correct polarity and connection.If absent, attach a known-good buzzer and retest.Only after confirming the speaker should you interpret beep codes or their absence as motherboard faults.Cross-check with motherboard LEDs or POST code displays if available. Verification / Alternative check: Shorting the reset or intentionally removing RAM should trigger a beep pattern if the speaker is working; continued silence points to the speaker path. Why Other Options Are Wrong: Monitor state and keyboard presence do not prevent a chassis beep. 'Normal boot' often still emits a single short beep on some systems, but many boards are silent by design—hence the need to verify the speaker first. Common Pitfalls: Assuming a silent POST equals a dead motherboard without checking the speaker hardware and BIOS settings that mute beeps. Final Answer: Bad or disconnected speaker

Question 14

Windows mapped drives: A previously successful mapped network drive disappears after every reboot. What is the most likely reason?

Accepted Answer

Introduction / Context: In Windows environments, mapped network drives can be configured to reconnect automatically at user logon. If the persistence option is not set, drive letters created during a session vanish upon restart, confusing users who expect the mapping to be permanent. Given Data / Assumptions: The drive mapping works during the current session. After reboot/logon, the mapping is gone. User-level mapping (not a startup script) was used. Concept / Approach: When mapping via File Explorer or 'net use', choosing 'Reconnect at logon' (or using '/persistent:yes') stores the mapping so Windows restores it automatically. If this box is not checked, the mapping is temporary. Other causes (server moved, legacy AUTOEXEC.BAT, last drive settings) are less relevant to modern Windows mapping behavior. Step-by-Step Solution: Open 'Map Network Drive' dialog.Ensure the checkbox 'Reconnect at logon' is selected (or run: net use Z: \server\share /persistent:yes).Provide credentials and optionally save them if cross-domain.Reboot to confirm the mapping persists. Verification / Alternative check: Use 'net use' in a Command Prompt to verify persistence. Group Policy or logon scripts can also enforce persistent mappings. Why Other Options Are Wrong: Server relocation would break the mapping immediately, not just after reboot. AUTOEXEC.BAT is irrelevant in modern Windows for drive mappings. 'Last drive' is a DOS-era concept and does not affect Windows network drive persistence. Common Pitfalls: Mapping with elevated rights different from the user session, or using credentials that are not saved, can also cause disappearances; however, the most common cause is simply not enabling reconnect at logon. Final Answer: You didn't click reconnect on log on

Question 15

PC I/O connectors and legacy storage:  On a typical expansion I/O controller card, the 34-pin ribbon-cable header is intended for which device interface?

Accepted Answer

Introduction / Context: Legacy PC storage interfaces used distinct ribbon-cable connectors with specific pin counts and keyed notches. Correctly identifying these headers prevents mis-wiring, boot failures, or device damage. The 34-pin header is historically associated with the floppy-disk subsystem on ISA/PCI I/O cards and on some motherboards. Given Data / Assumptions: A classic desktop I/O controller card provides multiple headers (for example, floppy, IDE/PATA, and sometimes serial/parallel). We are distinguishing among common legacy device buses: floppy (FDD), IDE/PATA, SCSI, and removable Zip drives (which themselves used IDE, SCSI, or parallel variants depending on model). Goal: map the 34-pin connector to the correct device type. Concept / Approach: Pin-count recognition is the fastest way to identify legacy buses. Floppy: 34-pin, narrow ribbon, with a characteristic “twist” section for drive A/B selection. IDE/PATA: 40-pin (desktop) or 44-pin (2.5-inch laptop with power). Narrow SCSI for internal devices typically uses a 50-pin ribbon (older) or 68-pin high-density for later generations. Zip drives did not have a unique pin count; internal Zip models were often IDE (40-pin) or SCSI (50-pin), while external units used parallel, USB, or SCSI connectors. Step-by-Step Solution: Identify connector pin count: header has 34 pins.Recall mapping: 34-pin equals floppy-disk interface; 40/44-pin equals IDE/PATA; 50/68-pin equals SCSI variants.Confirm physical clues: keyed notch, missing pin (for orientation), and cable twist section typical for floppy cables.Conclude the 34-pin header is for the floppy drive controller. Verification / Alternative check: Controller card silkscreen labels like “FDD” or “FLOPPY” near the 34-pin header corroborate the identification. Motherboard manuals list the 34-pin FDD header separately from 40/44-pin IDE connectors. Why Other Options Are Wrong: SCSI drive: typical internal narrow SCSI uses 50 pins (or 68 pins for wide SCSI), not 34. IDE drive: desktop IDE/PATA uses 40 pins; laptop 2.5-inch uses 44 pins. Zip drive: no unique 34-pin interface; internal versions rode IDE or SCSI, externals used other buses. None of the above: incorrect because “floppy drive” matches exactly. Common Pitfalls: Confusing the 34-pin floppy header with a 40-pin IDE when connectors are close together; ignoring keyed orientation leading to reversed cables; forgetting the cable “twist” that determines drive select; assuming Zip has a proprietary motherboard header (it does not). Final Answer: floppy drive

Question 16

Modem control using the Hayes/AT command set:  Which AT command is used to hang up (disconnect) the modem connection?

Accepted Answer

Introduction / Context: Before broadband and USB modems, dial-up devices were controlled by the Hayes AT command set. Understanding basic AT commands remains useful for embedded modems, terminal servers, and telecom labs where legacy procedures persist. Given Data / Assumptions: The question refers to the widely adopted Hayes “AT” command syntax. The goal is to terminate an active call and force the modem on-hook. Standard commands like ATD (dial), ATH (hang up), ATZ (reset) are assumed known. Concept / Approach: The Hayes set uses mnemonic letters following the “AT” prefix. “H” stands for hook control. ATH places the modem on-hook (disconnects), while ATH1 can force off-hook. ATD triggers dialing, and ATZ resets the modem to defaults and re-executes stored profile. ATR is not a standard hang-up command; it is typically used for reading settings on some devices but is not the hang-up control. Step-by-Step Solution: Identify action needed: hang up (go on-hook).Recall mapping: H = hook, D = dial, Z = reset.Select ATH to drop the connection and return to command state.Optionally use +++ escape sequence to enter command mode before issuing ATH if in data mode. Verification / Alternative check: Any terminal session to a classic modem confirms ATH returns “OK” and drops carrier. Documentation from Hayes-compatible devices lists ATH as the disconnect command. Why Other Options Are Wrong: ATZ: resets the modem; may also drop the call but is not the proper hang-up command. ATD: initiates dialing, opposite of disconnect. ATR: not the hang-up function; behavior varies by vendor. None of the above: incorrect because ATH is exactly right. Common Pitfalls: Issuing commands while still in data mode; forgetting the escape sequence “+++” and guard time; assuming ATZ is the safest disconnect (it can alter settings if profiles change). Final Answer: ATH

Question 17

Ohmmeter usage and safety:  When measuring resistance with a multimeter, how should the component or circuit be prepared for an accurate reading?

Accepted Answer

Introduction / Context: An ohmmeter injects a small known current and measures the resulting voltage to calculate resistance. Measuring resistance on a live or connected circuit causes false readings and can damage the meter. Proper isolation ensures accuracy and safety. Given Data / Assumptions: A standard digital multimeter with an ohms function is used. We want the resistance of a component, not the combined resistance of parallel paths. The circuit may otherwise be energized or have stored charge (capacitors). Concept / Approach: To measure resistance correctly, the component must be isolated from the rest of the circuit so that no alternate current paths exist. This is achieved by “breaking the circuit”—disconnecting at least one lead of the component—or by removing the component entirely. Power must be off; any residual voltage sources should be discharged to avoid meter damage and incorrect readings. Step-by-Step Solution: Turn off and unplug the equipment; wait for capacitors to discharge or discharge safely.Open the circuit at one end of the component (lift a lead) to remove parallel paths.Set meter to an appropriate ohms range.Measure across the isolated component terminals and record the resistance. Verification / Alternative check: Compare the measured value to the component’s color code or datasheet tolerance. Reconnect and test circuit function to confirm the component behaves as expected under operation. Why Other Options Are Wrong: In parallel/in series: these describe circuit connections, not preparation steps for resistance measurement. After checking voltage/current: measuring voltage/current is useful, but it does not satisfy the isolation requirement for an accurate ohms reading. Common Pitfalls: Measuring resistance with power applied; not isolating one leg so parallel paths lower the reading; not accounting for lead resistance on very low ohm measurements; failing to discharge capacitors which can momentarily drive the meter. Final Answer: after breaking the circuit

Question 18

Understanding POST (Power-On Self-Test):  During system boot-up, what does the memory test performed by POST actually do?

Accepted Answer

Introduction / Context: POST is firmware code that verifies key hardware before handing off to the bootloader/OS. Its memory test detects missing, mis-seated, or faulty RAM, reducing cryptic crashes later in the boot process. Given Data / Assumptions: The system is a PC-class machine with BIOS/UEFI firmware. POST runs immediately after power-on and before OS boot. The focus is specifically the RAM test behavior. Concept / Approach: The memory portion of POST typically performs a quick write/read verification across address ranges to confirm the presence and basic integrity of system RAM. It ensures detected memory is contiguous and usable by the firmware/OS, flags parity/ECC issues, and may display a count-up of available memory. Modern fast-boot options may shorten the test, but the intent remains validation rather than mere display. Step-by-Step Solution: System powers on; CPU executes firmware reset vector.POST initializes chipset, then probes memory controllers and DIMMs.Firmware performs pattern tests (write/read) over addresses to verify presence and contiguity.On success, firmware reports memory size and continues boot; on failure, it issues codes/beeps. Verification / Alternative check: Diagnostic tools (memtest-style) extend this idea with longer patterns, but the basic POST memory test confirms at least minimal operational integrity and mapping of contiguous blocks. Why Other Options Are Wrong: Superfluous/operational error: POST memory test is essential, not a mistake. Display only: POST does more than display; it validates by read/write tests. None of the above: incorrect because option stating verification is correct. Common Pitfalls: Assuming a fast memory count guarantees perfection; it is a basic screen, not an exhaustive test. Mixing DIMM speeds/types can pass POST but fail under load; ECC errors may be logged later even if POST completes. Final Answer: Checks and verifies that contiguous memory is installed

Question 19

Interpreting broad diagnostic failures:  A PC diagnostic reports simultaneous faults in the hard drive, CPU, RAM, and video card. What should you do first to resolve the situation logically and avoid unnecessary part swaps?

Accepted Answer

Introduction / Context: When a single diagnostic flags multiple unrelated subsystems as failing, the probability of a tool or configuration issue is higher than the likelihood that all devices failed simultaneously. Sound troubleshooting begins with validating the test environment and software. Given Data / Assumptions: The diagnostic runs within an OS or preboot environment. Reported failures span CPU, RAM, GPU, and storage. No prior symptoms conclusively point to catastrophic hardware failure across subsystems. Concept / Approach: Apply the principle of parsimony: a single cause (corrupt diagnostic, wrong drivers, OS instability, malware, overheating throttling) can explain multiple false positives. Therefore, verify software integrity, ensure a clean boot, update the diagnostic utility, and check system logs before replacing hardware. Only after software and environmental causes are excluded should you move to targeted hardware tests. Step-by-Step Solution: Reboot into a known-good environment (clean OS or bootable diagnostic media).Update or reinstall the diagnostic; verify checksums if available.Re-run tests while monitoring temperatures and power rails.Escalate to component-specific tests (memtest, storage SMART/long tests, GPU stress) only if issues persist. Verification / Alternative check: Cross-validate with a second diagnostic suite. If the second tool reports normal behavior, the initial tool or environment was at fault. If multiple tools agree on a single failing component, focus replacement there. Why Other Options Are Wrong: Replace parts one-by-one or all at once: costly and premature without confirming the test validity. Get another copy of the diagnostic: useful, but the first action should be to rule out a software/OS issue more broadly (drivers, corruption, malware, unstable overclocks). Exhaustive memory check: valuable later, but not the global first step when everything appears to fail. Common Pitfalls: Chasing multiple red herrings, ignoring power/thermal issues that can cause widespread errors, overlooking known-good boot media, and assuming the diagnostic is infallible. Final Answer: check to see if you have a software problem

Question 20

Laser printer maintenance outcome:  After servicing a laser printer, you notice dirty or smudged output. Which immediate action is most likely to clear residual toner and restore clean prints?

Accepted Answer

Introduction / Context: Laser printers use a toner/OPC drum/transfer/fuser process. After servicing, loose toner or contamination on the paper path can cause dirty prints. A simple clearing action often resolves residual smudging without invasive steps. Given Data / Assumptions: Printer has just been opened or serviced (for example, toner/drum replacement, cleaning, jam removal). Output shows light backgrounding, specks, or faint streaks indicative of stray toner. No specific component failure has been diagnosed yet. Concept / Approach: Residual toner in the developer area, transfer path, or fuser exit can deposit onto paper. Feeding several blank sheets allows the paper path to wipe and carry away loose toner. If smudging persists, deeper cleaning or component replacement (drum/fuser) may be needed, but the least-invasive remedy should be attempted first. Step-by-Step Solution: Load plain paper and print or feed several blank pages.Observe whether backgrounding or specks diminish after 3–10 sheets.If issues persist, inspect the toner cartridge, drum, transfer roller, and fuser for contamination or wear.Replace consumables if near end of life, and verify with a test page. Verification / Alternative check: Many vendors recommend printing blank pages after cartridge installation. If a new cartridge immediately resolves the issue, the original cartridge likely leaked or was contaminated. Why Other Options Are Wrong: Clean the developer tank / laser diode: advanced steps not typically required first; the laser assembly rarely causes “dirty” output. Reset the printer: does not remove toner from the paper path. None of the above: incorrect because running blank pages is a standard clearing technique. Common Pitfalls: Touching the OPC drum surface with fingers, using abrasive cloths inside the printer, or neglecting to check the transfer roller. Always follow vendor cleaning procedures. Final Answer: Run several blank pages

Computer Hardware Questions