Question 1

Basic electrical units – Capacitance is measured in which SI unit?

Accepted Answer

Introduction / Context: Knowing SI units is fundamental to electronics. Capacitance quantifies a component’s ability to store electric charge relative to voltage, and it appears in timing circuits, filters, power supplies, and RF networks. Given Data / Assumptions: We are identifying the SI unit associated with capacitance. Standard relationships between charge, voltage, and current apply. No trick context—straight definition. Concept / Approach: Capacitance C is defined by C = Q / V, where Q is charge in coulombs and V is voltage in volts. The SI unit derived from this definition is the farad (F). Practical capacitors are often specified in microfarads (µF), nanofarads (nF), or picofarads (pF) since one farad is a large unit for discrete components. Step-by-Step Solution: Recall definition: C = Q / V.Units: Q in coulombs, V in volts → C in coulombs per volt.By SI convention, coulomb per volt is called a farad.Therefore, the correct unit is the farad (F). Verification / Alternative check: Dimensional analysis: 1 F = 1 C/V = 1 s/ohm. Data sheets for capacitors list values in µF, nF, or pF, confirming industry usage. Why Other Options Are Wrong: Volts and amps measure electrical potential and current, not capacitance. “Neutrinos” and “anti-neutrinos” are subatomic particles and irrelevant to SI electrical units. Common Pitfalls: Confusing capacitance with capacitive reactance (measured in ohms); misreading datasheets where voltage rating (V) is listed alongside capacitance (F). Final Answer: Farads.

Question 2

Component units – A capacitor’s value is expressed in what unit?

Accepted Answer

Introduction / Context: Datasheets and schematics routinely specify capacitor values. Interpreting these correctly is critical for repairs, substitutions, and design changes in analog, digital, and RF circuits. Given Data / Assumptions: We seek the unit used to specify a capacitor’s capacitance value. Standard SI unit conventions apply. No special measurement context (e.g., ESR) is implied. Concept / Approach: The capacitance of a capacitor is measured in farads (F). Because 1 F is large, most components are labeled in microfarads (µF), nanofarads (nF), or picofarads (pF). Voltage printed on the capacitor is a rating, not the stored value. Step-by-Step Solution: Identify the physical quantity: capacitance (ability to store charge per volt).Unit association: farad = coulomb per volt.Typical markings: e.g., 100 nF, 10 µF, 47 pF, with a separate voltage rating like 16 V or 50 V.Hence, the correct unit is farads (F). Verification / Alternative check: Cross-check with formulae: Q = C * V and reactance Xc = 1/(2πfC), where C is in farads. Lab LCR meters read out in F, µF, nF, or pF. Why Other Options Are Wrong: Volts are a voltage rating; ohms measure resistance; “resistance” is not a unit and does not describe capacitance; “None of the above” is incorrect given farads is listed. Common Pitfalls: Confusing microfarads with millifarads; mixing nF and pF; overlooking polarity in electrolytics which is separate from capacitance magnitude. Final Answer: Farads (F).

Question 3

Legacy motherboard expansion – Most Pentium II/Pentium III era motherboards commonly supported which slot types?

Accepted Answer

Introduction / Context: During the Pentium II and Pentium III eras, motherboards evolved from legacy ISA toward PCI and the emerging AGP standard for graphics. Recognizing typical slot combinations is useful for maintenance and exam preparation. Given Data / Assumptions: Target timeframe: late 1990s to early 2000s (PII/PIII). Consumer/office ATX or similar motherboards. Common graphics interface of the time: AGP 1x/2x/4x. Concept / Approach: Many PII/PIII boards offered a mix of legacy ISA for older expansion cards, PCI for mainstream devices, and AGP for accelerated graphics. EISA was largely confined to servers/workstations earlier in the decade, and MCA was IBM-specific. VLB was prevalent in 486-era boards and disappeared by the PII timeframe. Step-by-Step Solution: Identify contemporary bus standards: ISA (legacy), PCI (main), AGP (graphics).Match to PII/PIII era: AGP introduced with Pentium II; PCI prevalent; some ISA retained for sound/modems.Eliminate outdated or niche combinations (MCA, EISA, VLB).Therefore, ISA + PCI + AGP is the correct typical set. Verification / Alternative check: Motherboard manuals from that era show several PCI slots, one AGP slot, and one or two ISA slots. Retail listings and photos confirm this configuration. Why Other Options Are Wrong: MCA is incompatible with standard PCs; EISA is rare in consumer boards; VLB predates PII/PIII and was phased out by PCI/AGP. Common Pitfalls: Confusing workstation/server boards with consumer boards; assuming ISA was already gone—many PIII boards still included one ISA slot for compatibility. Final Answer: ISA, PCI, and AGP.

Question 4

Testing a fuse with an ohmmeter – What resistance reading indicates a good fuse in a high-current system?

Accepted Answer

Introduction / Context: Fuses protect circuits by opening when current exceeds a rated value. A quick continuity or resistance test confirms the fuse's condition. Understanding expected readings helps avoid unnecessary replacements and downtime. Given Data / Assumptions: The fuse is removed from the circuit (best practice) or the circuit is unpowered. Ohmmeter/DMM is functioning and leads are zeroed if needed. Fuse is rated for high current (very low internal resistance when intact). Concept / Approach: A good fuse behaves like a short conductor and should measure very close to 0 Ω. Small readings such as 0.1–0.2 Ω can be due to lead resistance or contact resistance. Any reading in the multi-ohm range indicates excessive resistance or an open fuse. Step-by-Step Solution: Set DMM to low-ohms range; short probes to note lead resistance.Measure fuse from cap to cap with firm contact.Interpretation: reading ≈ 0.0 Ω (or near lead resistance) → fuse is good.High resistance or “OL” → fuse blown or degraded. Verification / Alternative check: Continuity mode with audible beep can confirm low resistance. Visual inspection may reveal a broken element, but ohmic testing is more reliable for time-delay types. Why Other Options Are Wrong: 0.2 Ω can be acceptable in some meters, but the best expected answer is essentially 0 Ω. Readings like 2 Ω or 5 Ω are far too high for a healthy, high-current fuse. Common Pitfalls: Testing in-circuit and reading parallel paths; not subtracting lead resistance; poor probe contact causing artificially high readings. Final Answer: 0.0 Ω (essentially short, near zero).

Question 5

Peripheral conflicts – System locks up when parallel-port tape backup is used after installing a sound card What is the most likely cause of the freeze?

Accepted Answer

Introduction / Context: Legacy PCs often rely on fixed or limited interrupt (IRQ) and DMA resources. Adding a new sound card can inadvertently overlap with resources used by a parallel-port peripheral (such as a tape backup), leading to hangs or nonresponsive devices. Given Data / Assumptions: System worked before; problem appears when the parallel-port tape unit is active after installing a sound card. Operating system uses classic ISA/PCI resource allocation without robust automatic conflict resolution. LPT port typically uses IRQ7 (or IRQ5 in some configurations). Concept / Approach: Sound cards frequently used IRQ5/7 and DMA channels (e.g., DMA1, DMA5) for legacy compatibility. Parallel-port devices may use IRQ7 for event-driven I/O. If both attempt to use the same IRQ simultaneously, interrupt handling becomes unstable, causing lockups or device failures. Resolving the conflict requires reassigning IRQs or changing port modes. Step-by-Step Solution: Open Device Manager (or BIOS for legacy cards) and note IRQ assignments.Check LPT settings (ECP/EPP modes may also consume DMA channels).Move the sound card to a different slot or manually set it to a different IRQ (e.g., IRQ5) and adjust DMA if needed.Retest the tape backup operation to verify stability. Verification / Alternative check: Disable the sound card temporarily; if the tape unit works normally, re-enable sound with a different IRQ/DMA configuration. Event logs or diagnostic tools may confirm shared IRQs in conflict-prone configurations. Why Other Options Are Wrong: DMA issues can occur, but parallel-port tape hangs after sound installation most commonly reflect an IRQ clash. Declaring either device defective ignores the timing correlation and classic resource overlap symptoms. Driver faults are possible but less likely than a straightforward interrupt conflict in this scenario. Common Pitfalls: Forgetting ECP mode uses a DMA channel; assuming PCI devices can safely share IRQs like modern systems—older OSes and drivers were less tolerant; leaving BIOS on “PnP OS = No” or vice versa causing static allocations that collide. Final Answer: IRQ conflict between the sound card and the parallel port/tape device.

Question 6

Legacy Modem Fundamentals  In traditional PC communications, external and internal dial-up modems exchange data with the computer using which style of data transmission (bit timing and framing method)?

Accepted Answer

Introduction / Context: Classic dial-up modems interfaced with PCs long before broadband and USB became common. Understanding how a modem frames and times data clarifies why serial port settings like baud rate, data bits, parity, and stop bits matter. This question asks which transmission style a modem uses when talking to the computer's serial (COM) port. Given Data / Assumptions: PC hosts communicate with external or internal modems via a serial interface. Settings such as 8-N-1 (8 data bits, no parity, 1 stop bit) are familiar defaults. The telephone network path between two modems is analog; the PC-to-modem link is digital serial. Concept / Approach: On the PC side, modems use asynchronous serial transmission. Each character is framed by a start bit and one or more stop bits, with optional parity. There is no separate clock line; timing is derived from the configured baud rate. While modems can perform complex synchronous protocols over the phone line, the host connection itself is almost universally asynchronous for desktop use. Step-by-Step Solution: Note the typical serial configuration: baud rate (e.g., 9600), data bits, parity, and stop bits.Recognize that the presence of start/stop framing indicates asynchronous transmission.Recall that synchronous links would require clocking or special protocols not used by standard COM-port modem control.Therefore, the correct selection is asynchronous. Verification / Alternative check: Terminal programs (e.g., HyperTerminal, PuTTY) require asynchronous settings (8-N-1) to communicate with AT-command modems. This operational fact confirms the answer. Why Other Options Are Wrong: Synchronous requires shared clocking not present on classic PC COM links. “Timed interval,” “ata,” and “bank” are not valid transmission modes for serial communication. Common Pitfalls: Confusing the modem-to-modem line protocol with the PC-to-modem interface. The PC side is asynchronous even if modems negotiate complex protocols over the phone line. Final Answer: asynchronous

Question 7

PC I/O Identification  On a classic desktop PC, a 25-pin female D-sub connector on the rear panel typically corresponds to which interface?

Accepted Answer

Introduction / Context: Correctly identifying legacy PC connectors is essential for troubleshooting printers, modems, and other peripherals in labs or support environments. Two look-alike ports often cause confusion: serial and parallel. This item focuses on the 25-pin female connector. Given Data / Assumptions: Legacy AT/ATX PC rear panel with D-sub connectors. 25-pin female and 9-pin male connectors are present. We are concerned with typical, standards-compliant configurations. Concept / Approach: Standard PC parallel ports (LPT1/LPT2) use a DB-25 female connector for printer connections. Serial ports are usually DB-9 male (later PCs) or DB-25 male (earlier systems). Thus, a DB-25 female on the back is most commonly the parallel (printer) port, not a serial COM port. Step-by-Step Solution: Identify connector gender and pin count: 25-pin female.Recall mapping: DB-25 female → LPT (parallel), DB-9 male → COM (serial).Therefore, conclude it is a parallel port interface. Verification / Alternative check: Check BIOS/UEFI I/O configuration for LPT1 set to a typical base address (378h) that corresponds to the DB-25 female connector. Why Other Options Are Wrong: “Serial port 1” (COM1) is normally DB-9 male. “COM2 port” is also serial and normally DB-9 male. “Docking” is not a rear DB-25 female. Hence, “None of the above” is unnecessary. Common Pitfalls: Assuming all DB-25 connectors are serial. Remember: gender matters—female DB-25 on the PC is parallel by convention. Final Answer: A parallel port

Question 8

Internal Modem Resource Conflicts  When installing an internal modem in a legacy PC, which of the following IRQs would not normally be assigned to the modem?

Accepted Answer

Introduction / Context: ISA-era modems required manual configuration of I/O ports and interrupt requests (IRQs). Knowing typical assignments prevents conflicts with other devices like hard-disk controllers and printers. This question asks which IRQ is not appropriate for a modem. Given Data / Assumptions: Legacy ISA resources: common modem COM assignments are to IRQ3 or IRQ4. Other IRQs (5, 10) may be available depending on system configuration. Standard IDE hard-disk controllers occupy a specific IRQ. Concept / Approach: Hard-disk controllers traditionally use IRQ14 (primary IDE). Assigning IRQ14 to a modem would conflict with disk I/O, causing system instability or device failure. Modems typically use IRQ3/4; occasionally IRQ5 or IRQ10 is used in some setups, but not IRQ14. Step-by-Step Solution: List usual modem IRQs: 3 or 4; sometimes 5 or 10.Recall that IRQ14 is reserved by the IDE primary controller.Therefore, IRQ14 is the one that should not be used for a modem. Verification / Alternative check: Check Device Manager on AT-class systems; the IDE controller shows IRQ14. Hardware manuals also document this default mapping. Why Other Options Are Wrong: IRQ5 and IRQ10 can be valid choices in some configurations; “All of the above” is too broad, and “None of the above” ignores the standard IDE usage of IRQ14. Common Pitfalls: Forgetting that printer ports and sound cards historically used IRQ7/5 respectively, and confusing COM port defaults with IDE assignments. Final Answer: 14

Question 9

Disk Geometry Basics  A hard disk platter is divided into concentric tracks. Each track is further subdivided into which fundamental storage unit used by the controller for addressing and reads/writes?

Accepted Answer

Introduction / Context: Understanding the physical and logical organization of magnetic storage helps when interpreting low-level diagnostics and formatting concepts. The hierarchy includes platters, tracks, and smaller addressable units within each track. This question targets the name of those smallest units on a track. Given Data / Assumptions: Conventional hard drives with CHS (cylinder/head/sector) legacy terminology. Modern LBA abstracts CHS, but sectors remain the smallest addressable unit. Typical sector size historically 512 bytes (now also 4096-byte Advanced Format). Concept / Approach: A track is divided into sectors, each with data plus overhead (sync, header, ECC). File systems group sectors into clusters (allocation units), but at the disk level the controller reads and writes sectors. Step-by-Step Solution: Identify the physical division: platter → tracks.Within each track, the controller addresses sectors.Therefore, the correct term for the subdivision is “sectors.” Verification / Alternative check: Low-level tools display sector counts; SMART attributes and disk imaging utilities operate in units of sectors or logical block addresses (LBAs). Why Other Options Are Wrong: Clusters are file-system constructs grouping sectors. “Vectors” is not a disk geometry term. “Heads” refer to read/write elements and surfaces, not subdivisions of a track. Common Pitfalls: Confusing sectors (hardware unit) with clusters (file system unit) when interpreting capacity and fragmentation. Final Answer: sectors

Question 10

PC Logic Supply Levels  On most digital circuit boards inside a PC, which DC voltage rail is the primary supply used by TTL/CMOS logic ICs and many controllers?

Accepted Answer

Introduction / Context: Personal computer power supplies provide multiple DC rails for different purposes. Recognizing which voltage powers the bulk of logic ICs helps in diagnostics and power testing. This question asks for the most common logic rail on traditional motherboards and add-in cards. Given Data / Assumptions: Legacy AT/ATX designs with rails including +12 V, +5 V, +3.3 V, and negative rails. Many classic TTL/CMOS parts and older controllers use +5 V. Modern chipsets often use local regulators to derive lower voltages, but +5 V remains common for legacy logic and peripherals. Concept / Approach: Historically, +5 V is the primary logic supply for TTL families and numerous peripheral ICs. +12 V powers motors and some analog circuits; 0 V is ground reference; −12 V supports certain serial interfaces or analog sections. Therefore, the best single choice for “most circuit boards” is +5 V. Step-by-Step Solution: List rails and common uses: +12 V (motors, fans), +5 V (logic), −12 V (legacy serial), 0 V (ground).Identify the dominant logic rail as +5 V for classic boards.Conclude +5 V is the correct answer. Verification / Alternative check: Board silkscreens, regulator inputs, and PSU label diagrams confirm +5 V as a primary logic feed in many systems. Why Other Options Are Wrong: −12 V is niche; 0 V is ground, not a supply; +12 V is typically for drives and fans. “None of the above” is unnecessary. Common Pitfalls: Assuming newer low-voltage cores negate +5 V usage entirely; many interfaces and legacy devices still rely on +5 V. Final Answer: +5 volts

Question 11

No-Display Troubleshooting Checklist  When a user reports “no display,” which initial question best helps determine whether the display subsystem is functioning at a basic level?

Accepted Answer

Introduction / Context: “No display” can originate from the monitor, GPU, cable, power, or POST failure. Smart triage questions quickly isolate whether the system is powering, posting, and driving the screen. This item asks which checks are useful as a first pass. Given Data / Assumptions: A conventional desktop or laptop with a separate or integrated display. Technician can query user/observe system immediately after power-on. Standard POST beep codes and monitor HV behavior are relevant. Concept / Approach: All three prompts provide complementary evidence. A visible cursor or on-screen activity shows the GPU/monitor path is working. A POST beep or chime indicates the system has initialized core hardware. Feeling/hearing high-voltage static on CRTs (or power/LED and backlight activity on LCDs) indicates the monitor powers up. Together, they rapidly narrow the fault domain. Step-by-Step Solution: Ask about any on-screen text, cursor, or backlight glow.Confirm POST beeps/chimes and other signs (keyboard LEDs flash).Check monitor power: indicator LED, relay click, or HV static (for CRTs).If absent, test with a known-good cable/monitor and reseat the GPU/RAM. Verification / Alternative check: Connect an external display, use onboard graphics, or run with minimal hardware. Each check corroborates the initial triage. Why Other Options Are Wrong: Each single question alone may miss failures; all together provide broader coverage. Thus, the combined option “All of the above” is best. Common Pitfalls: Ignoring beep codes, overlooking loose cables, or forgetting to test with a different monitor input (HDMI/DP selection). Final Answer: All of the above

Question 12

Throughput Naming: What Does “14.4 Modem” Mean?  A so-called 14.4 modem is named for its nominal data rate. Approximately how many bits per second does it transmit under ideal link conditions on the line side?

Accepted Answer

Introduction / Context: Modem model names historically reflected nominal maximum line rates. Interpreting those labels helps set expectations and recognize marketing claims. The classic “14.4” refers to a specific kilobits-per-second class of modems common in the early 1990s. Given Data / Assumptions: The term “14.4 kbps” denotes 14.4 * 10^3 bits per second on the modem-to-modem link. Actual throughput after error correction and protocol overhead may be lower or aided by compression to be higher in effective terms. We are matching the rough numeric range provided in the choices. Concept / Approach: “14.4 kbps” equals approximately 14,400 bits per second. Among the options, the range 14,400–15,000 bps is the only one bracketing the conventional value, making it the best match to the modem's nominal speed class. Step-by-Step Solution: Recognize that “14.4” implies 14.4 kbps ≈ 14,400 bps.Scan the options for a range containing 14,400.Select the option 14,400–15,000 bps as the correct approximation. Verification / Alternative check: Historical modem standards (V.32bis) specify a 14,400 bps rate tier, consistent with the name. Why Other Options Are Wrong: 140–150 and 1400–1500 are far below; 140,000–150,000 is far above. “None of the above” is invalid because a correct approximate range is provided. Common Pitfalls: Confusing kilobits with kilobytes per second, or overlooking protocol overhead when estimating real-world throughput. Final Answer: 14,400-15,000

Question 13

CRT Safety Procedure  Before discharging a cathode-ray tube (CRT) in a computer display for service, what is the first safety step you should perform?

Accepted Answer

Introduction / Context: CRTs operate at high voltages and can retain charge after power-off. Discharging a CRT must follow strict safety steps to avoid shock and equipment damage. This question asks for the very first action before any discharge procedure begins. Given Data / Assumptions: Technician is preparing to service a CRT-based display. Standard ESD and electrical safety practices apply. Proper discharge tools and PPE are available. Concept / Approach: Always remove power before servicing high-voltage equipment. Power the unit down and unplug it from the mains. Only after confirming the unit is de-energized should you proceed to properly discharge the anode using an insulated tool connected to chassis ground via a resistor. Step-by-Step Solution: Shut down and switch off the display.Unplug the power cord to eliminate mains voltage.Wait an appropriate interval for bleeder resistors to reduce charge.Perform controlled discharge of the CRT anode to chassis ground with a proper HV discharge tool. Verification / Alternative check: Use a voltmeter or follow manufacturer guidelines to confirm residual voltage is dissipated before touching HV areas. Why Other Options Are Wrong: Removing parts before ensuring power is off increases hazard. Merely disconnecting video or removing assemblies does not address dangerous HV. Thus, the first step must be powering off and removing the power source. Common Pitfalls: Assuming power off is enough without unplugging, or using ad-hoc tools for discharge. Always follow approved procedures and use insulated tools. Final Answer: Turn power off before removing power source

Question 14

DMA Resource for Floppy Controller  On legacy PCs, the floppy disk controller (FDC) uses which ISA DMA channel for data transfers?

Accepted Answer

Introduction / Context: ISA-era systems assign fixed DMA channels to certain controllers. Recognizing these defaults helps diagnose resource conflicts and configuration issues. The floppy disk controller is one of the classic examples with a well-known DMA assignment. Given Data / Assumptions: Standard PC/AT mapping with dual 8237 DMA controllers (8-bit and 16-bit channels). A conventional floppy disk drive and controller are present. We are referring to ISA-based systems. Concept / Approach: The FDC conventionally uses 8-bit DMA channel 2 for data transfers. Other standard mappings include DMA channel 3 for LPT (in some modes) and higher channels for 16-bit devices. Remembering “FDC → DMA 2” is a common A+ and hardware exam fact. Step-by-Step Solution: Recall ISA DMA assignments: channel 2 is reserved for floppy operations.Cross-check typical I/O base of FDC (3F0–3F7) alongside the DMA channel.Select channel 2 as the correct choice. Verification / Alternative check: View Device Manager on old systems or BIOS setup to confirm the FDC uses DMA 2. Vendor manuals also list this mapping. Why Other Options Are Wrong: Channels 1, 4, 5, and 9 are not the default for the floppy controller in ISA PCs. Hence, option “2” is uniquely correct. Common Pitfalls: Confusing IRQs (e.g., FDC uses IRQ6) with DMA channels, or mixing up printer DMA usage with floppy. Final Answer: 2

Question 15

Handling 5¼-Inch Floppy Media  When not in use, what is the recommended storage practice for 5¼-inch floppy diskettes to minimize dust, abrasion, and magnetic damage?

Accepted Answer

Introduction / Context: Magnetic media like 5¼-inch floppies are susceptible to dust, scratches, humidity, and stray magnetic fields. Proper storage extends media life and protects the drive heads from contamination. This question asks for the best routine storage method when the diskette is idle. Given Data / Assumptions: Flexible 5¼-inch media in thin jackets. Presence of dust and mechanical abrasion risks in typical office or lab environments. Desire to preserve data integrity and physical condition. Concept / Approach: Protective sleeves shield the disk surface from dust and scratches while reducing static. Proper sleeves are designed for the media and allow safe handling. Additional measures include storing in cool, dry conditions away from magnets and sunlight. Step-by-Step Solution: Remove the diskette from the drive after use.Place it immediately in its protective paper or plastic sleeve.Store flat in labeled boxes, away from heat and magnetic fields.Avoid bending or stacking heavy objects on the media. Verification / Alternative check: Manufacturer handling guidelines universally recommend sleeve storage to minimize contaminants and abrasion. Why Other Options Are Wrong: Plastic bags can trap static and don’t control abrasion. Upright shelving without sleeves exposes media to dust and bending. Leaving a disk in the drive risks heat, contamination, and accidental write operations. Common Pitfalls: Touching the exposed media window, placing disks near speakers (magnets), or writing with ball-point pens directly on the jacket. Final Answer: Their protective sleeves

Question 16

Preventing data corruption due to power interruptions: Which device should you deploy so that power is not cut off unexpectedly and your system can continue running long enough to save work safely?

Accepted Answer

Introduction / Context: Unexpected power loss can corrupt open files, damage databases, and interrupt firmware updates. The most reliable way to bridge short outages and allow graceful shutdowns is to use a device that stores energy and instantly supplies it to connected equipment when mains power fails. This question tests your understanding of uninterruptible power strategies for computers and servers. Given Data / Assumptions: Goal: avoid immediate shutdown during brownouts or blackouts. Equipment: typical desktop or workstation with operating system and active storage. Risk: data loss and file-system corruption during an abrupt power cut. Concept / Approach: An Uninterruptible Power Supply (UPS) contains batteries (or other energy storage) and power electronics that provide conditioned power and instantaneous switchover to battery when the mains fails. Surge protectors and proper grounding improve safety and reduce transient damage, but they do not supply power during an outage. Therefore, only a UPS directly prevents interruption long enough to save work or perform an automated shutdown. Step-by-Step Solution: Identify the requirement: continuous power during short outages.Map solutions to functions: surge protector = clamps voltage spikes; grounding = safety and noise control; UPS = energy storage + inverter.Select the device that actually supplies power when utility power is lost: UPS.Optionally pair UPS with software to trigger an orderly shutdown when battery reaches a set threshold. Verification / Alternative check: During a simulated outage (disconnecting mains input), devices on a UPS should continue to run from battery; devices on only a surge protector will shut off immediately. Why Other Options Are Wrong: Proper grounding: Essential for safety and noise control but does not provide backup power. Surge protector: Mitigates spikes and surges; cannot power equipment during outages. Humorous distractor: Not a real electrical solution. None of the above: Incorrect because a UPS fulfills the requirement. Common Pitfalls: Confusing surge protection with ride-through capability, undersizing the UPS (insufficient VA/W), and forgetting to connect critical devices like network switches or external drives that also need continuous power. Final Answer: UPS

Question 17

Notebook cannot see an external drive: what checks should you consider before deeper diagnostics?

Accepted Answer

Introduction / Context: When a notebook fails to recognize an external drive (USB, Thunderbolt, or eSATA), the fastest resolution often comes from a structured basic checklist. Many incidents are caused by connection, power, or driver issues rather than hardware failure. Given Data / Assumptions: External storage enclosure or portable drive is being connected. Operating system normally supports plug-and-play storage. No explicit error message is provided yet. Concept / Approach: Always begin with fundamentals: physical connections, power state, and required software. Some enclosures require external power or a Y-cable for adequate current. Others need a vendor driver or encryption utility to expose volumes. Hot-plugging order can matter for certain legacy interfaces or older operating systems; replugging after boot sometimes triggers enumeration properly. Step-by-Step Solution: Confirm the drive's power switch (if present) is ON and the activity LED illuminates.Check cable seating, try a different USB/Thunderbolt port, and replace the cable if possible.Install any required device software or unlock utilities; verify the file system is recognized.Reboot and reconnect; check Disk Management for uninitialized or offline disks. Verification / Alternative check: Test the drive on a second computer. If it is recognized there, the issue may be OS drivers, security policies, or insufficient power on the original notebook port. Why Other Options Are Wrong: Each individual option addresses a real and common cause; since all are relevant, the combined choice that includes all of them is correct. Common Pitfalls: Using unpowered hubs for 2.5 inch spinning drives, overlooking disk initialization, and ignoring encrypted volumes that require software to mount. Final Answer: All of the above

Question 18

Setting a SCSI ID using jumpers (1 = shorted, 0 = open): On a three-bit jumper block, which bit pattern selects logical ID 3?

Accepted Answer

Introduction / Context: Legacy SCSI devices use hardware jumpers or DIP switches to set the device ID. Understanding binary weighting of the ID bits is essential when configuring multiple devices on the same bus to avoid conflicts and ensure proper enumeration by the host adapter. Given Data / Assumptions: Three ID bits are available, representing values 1, 2, and 4 (least to most significant). Convention: 1 = jumper shorted (logic high), 0 = open (logic low). Target ID is decimal 3. Concept / Approach: Binary representation maps decimal numbers to powers of two. Decimal 3 equals 2 + 1, which corresponds to setting the least significant two bits to 1 and the most significant to 0 when using a 3-bit field: 011 in binary (MSB to LSB). This pattern will program the device to ID 3 on the SCSI bus. Step-by-Step Solution: Express 3 in binary: 3 = 2 + 1 → bits (4,2,1) = (0,1,1).Apply the jumper rule: place jumpers on the 2 and 1 posts; leave the 4 post open.Verify no other device uses ID 3 or the host adapter's reserved ID (often 7).Power cycle and confirm the ID in the SCSI BIOS scan. Verification / Alternative check: Cross-check with the drive’s label or manual showing ID tables; 011 is universally shown for ID 3 on 3-bit SCSI ID blocks. Why Other Options Are Wrong: 100: Selects ID 4 (only MSB set). 010: Selects ID 2 (only the middle bit set). 101: Selects ID 5 (4 + 1). None of the above: Incorrect since 011 is valid for ID 3. Common Pitfalls: Reading bit order right-to-left incorrectly, mixing up the position of MSB/LSB on the header, and forgetting to remove termination on middle-of-bus devices. Final Answer: 011

Question 19

Where is the Power-On Self-Test (POST) routine stored that begins by counting system board RAM?

Accepted Answer

Introduction / Context: When a PC powers up, firmware runs diagnostic checks known as POST. One visible step is counting system memory. Knowing where these routines are stored clarifies the roles of ROM, CMOS, CPU, and RAM during boot. Given Data / Assumptions: Traditional PC architecture with a firmware chip (legacy BIOS) on the motherboard. CMOS holds configuration parameters with a battery. CPU executes instructions but does not store firmware code permanently. Concept / Approach: POST code is firmware residing in read-only memory (historically ROM, EPROM, or flash), commonly called the ROM BIOS. At reset, the CPU fetches instructions from a fixed address mapped to this firmware, which initializes hardware, counts RAM, and prepares to load the operating system. CMOS only stores settings (e.g., boot order, date/time); RAM is not yet initialized when POST begins and cannot contain the code that initializes itself. Step-by-Step Solution: Power applied → CPU reset vector points to firmware address space.CPU executes BIOS firmware stored in non-volatile memory (ROM/flash).POST routines run: chipset init, memory controller init, RAM count.Firmware then hands off to bootloader after device discovery. Verification / Alternative check: Flashing the BIOS updates the firmware image that includes POST routines. Removing the CMOS battery resets settings but does not erase the firmware code, confirming it is stored in ROM/flash. Why Other Options Are Wrong: RAM: Volatile and uninitialized at power-on; cannot contain POST. Microprocessor: Executes code but does not store it permanently. CMOS: Holds configuration data, not executable firmware. 8259: A programmable interrupt controller, not a storage location for POST. Common Pitfalls: Confusing CMOS setup utility (a program in ROM) with the CMOS memory that simply stores its settings. Final Answer: ROM BIOS

Question 20

On legacy IBM-compatible systems, a POST error code in the 6xx range typically indicates a problem with which device class?

Accepted Answer

Introduction / Context: Power-On Self-Test (POST) codes help technicians quickly narrow down failing subsystems. Classic IBM/PC-compatible BIOS families commonly used broad numeric ranges associated with device classes. Recognizing these ranges speeds diagnosis without digging through every setting. Given Data / Assumptions: Legacy BIOS conventions where 6xx codes relate to diskette (floppy) subsystems. Examples include codes such as 601 indicating a diskette drive or controller error. Other device classes (keyboard, hard disk) typically occupy different ranges (e.g., 301 keyboard). Concept / Approach: POST code families are mapped to hardware groups. In many legacy references, 6xx errors point to the diskette drive, cable, or controller problems. While exact codes can vary by BIOS vendor, technicians historically learned these common associations for fast triage before consulting the specific service manual. Step-by-Step Solution: Observe on-screen 6xx POST error.Associate the 6xx range with the floppy subsystem (drive A:, cable, controller).Inspect power/data cables and drive configuration (drive type, termination where applicable).Run further diagnostics or swap known-good cables/drive to confirm. Verification / Alternative check: Cross-reference the BIOS vendor’s POST table for exact meanings (e.g., 601 Diskette Drive Error). Replacing or reseating the floppy cable commonly resolves intermittent 6xx errors. Why Other Options Are Wrong: Hard drive: Typically 17xx, 1xx, or vendor-specific codes. Keyboard: Often 301/302, outside the 6xx family. CD-ROM: ATAPI/IDE optical issues rarely report as 6xx in classic BIOS tables. All of the above: Overly broad and not aligned with classic code ranges. Common Pitfalls: Assuming all BIOSes share identical codes; always verify with the exact system manual after using the range as a quick hint. Final Answer: Floppy drive

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