- What You Are Actually Studying
- Exam Mechanics: Format, Fees, and Test-Day Rules
- The Hardware Core: Domains 2 Through 9
- Domain 1: Why Safety Deserves Real Study Time
- Networking and Portables
- Troubleshooting, Operating Systems, and File Management
- Sequencing Your Preparation
- Prerequisites, Pathways, and the A+ Rollover
- After You Pass: Four-Year Maintenance
- Frequently Asked Questions
- The CST exam has 80 questions in two hours, requires 75% to pass, and is a proctored theory test with no hands-on portion.
- The exam fee is USD 80; remote proctoring through ExamRoom.AI adds USD 16, even on the free retake.
- Fourteen unweighted competency areas mean you cannot safely skip any domain, including Safety and File Management.
- One free retake is available within one year of your initial session, so failing once is not the end.
What You Are Actually Studying
The Computer Service Technician (CST) credential from ETA International tests whether you can service and support personal computer systems the way a working bench or field technician does. If you are still sorting out terminology, our explainers on what CST certification is and what CST stands for cover the basics. This guide focuses on the harder question: how to prepare efficiently and pass on your first sitting.
The exam is built from 14 official competency headings published in ETA's Computer Service Technician competency requirements document. Those headings are unweighted, meaning ETA does not publish a percentage for each one. That has a practical consequence: you should not budget your time around a guessed weighting. Instead, treat every domain as fair game and aim for solid competence across the entire list. For a deeper walk through each area, see the complete guide to all 14 CST content areas.
Another important detail is that ETA retains both legacy and current technologies in its competency language. A modern study plan built only around the newest hardware and software will leave gaps. Expect the exam to touch older interfaces, older operating systems, and long-standing concepts alongside current ones.
Exam Mechanics: Format, Fees, and Test-Day Rules
Knowing the logistics removes avoidable stress. Here is the format at a glance:
| Item | Detail |
|---|---|
| Issuing body | ETA International |
| Questions | 80 |
| Time limit | Two hours |
| Passing score | 75% |
| Exam fee | USD 80 |
| Remote proctoring fee | USD 16 (two-hour proctoring), also charged on a free retake |
| Hands-on component | None; proctored theory exam only |
| Retake | One free retake within one year of the initial session |
Two hours for 80 questions gives you an average of 90 seconds per question. That is comfortable for recall-style items but tighter for questions that require you to reason through a scenario or perform a calculation. A 75% threshold means you can miss up to 20 questions and still pass, so the goal is consistent accuracy rather than perfection. For the math and the implications, read our breakdown of the CST passing score.
Choosing Your Delivery Method
You have two routes. Onsite testing is administered by an ETA Certification Administrator, using either Trapeza online testing or paper and pencil. Remote proctoring runs through ExamRoom.AI, is arranged through ETA, and adds the USD 16 two-hour proctoring fee. If you retake the exam remotely, that fee applies again even though the retake itself is free. Budget accordingly, and see the full CST certification cost breakdown for the complete picture. If you are still working out timing, the CST exam dates and scheduling guide explains how to arrange a session.
What You Can and Cannot Bring
- Photo ID: required for check-in.
- Scratch paper: permitted, but used sheets must be surrendered at the end.
- Calculator: a non-programmable scientific calculator is allowed. Practice with the exact model you will carry so the keystrokes are automatic.
The Hardware Core: Domains 2 Through 9
Eight of the fourteen domains are hardware-centric, so this is where most of your study hours belong. The difficulty comes not from any single topic but from the breadth. Our look at how hard the CST exam is discusses why breadth, rather than depth, is what trips up many candidates.
Domain 2: Computer Assembly and Disassembly
Be able to reason through the order and technique of building and tearing down a system.
- Component installation sequence and orientation of connectors and cables
- Proper seating of memory, processors, and expansion cards
- Tools, fasteners, and handling practices during a build
- Verifying a system after reassembly
Domain 3: Motherboards / Mainboard and Buses / System Resources
Understand how the board ties everything together.
- Form factors and how they constrain case and power supply choices
- Expansion bus types, both legacy and current, and their relative characteristics
- System resources such as interrupts, DMA, and I/O addressing
- Firmware and configuration settings that affect hardware behavior
Domain 4: Processor Characteristics
Know what distinguishes processors and how they interact with the board.
- Sockets and compatibility with motherboards
- Clock speed, cache, and core concepts
- Cooling requirements and thermal considerations
- Features that affect performance and system behavior
Domain 5: Additional Memory Characteristics
Memory questions reward precise vocabulary.
- Memory types and module formats, including older and newer generations
- Speed and capacity relationships
- Compatibility between modules, boards, and processors
- Symptoms of memory problems and how to isolate them
Domain 6: Secondary Storage Devices
Storage spans decades of technology, and the exam reflects that.
- Magnetic, optical, and solid-state storage characteristics
- Drive interfaces, cabling, and configuration
- Partitioning and formatting concepts at the hardware-to-software boundary
- Capacity, speed, and reliability tradeoffs
Domain 7: Adapter Cards and Peripheral Devices
Connect the card, the slot, the driver, and the symptom.
- Video, sound, network, and other expansion card functions
- Matching cards to compatible bus slots
- Peripheral device installation and driver considerations
- Display and output device characteristics
Domain 8: Input/Output (I/O) Ports
Port questions often test recognition and capability.
- Serial, parallel, USB, and other port types, including legacy connectors
- Connector shapes, pin counts, and typical uses
- Relative data-transfer capabilities of each interface
- Cable types and length or compatibility constraints
Domain 9: Power Concepts and Power Supplies
Power ties electronics fundamentals to practical service work.
- AC and DC concepts and how a supply converts between them
- Output voltages, connectors, and wattage planning
- Surge protection and power conditioning devices
- Diagnosing power-related failures safely
Because ETA's materials retain legacy technologies, do not skip an older interface or standard just because you rarely see it in the field today. If it is named in the competency requirements, it is eligible to appear.
Domain 1: Why Safety Deserves Real Study Time
Many candidates treat Safety Procedures / Handling / Environmental Awareness as the easy domain and give it a quick skim. That is a mistake, because it is the foundation of the entire competency list and an area where questions are often answerable only if you know the precise preferred practice.
- Electrostatic discharge: how it damages components and the protective measures against it
- Safe handling of components, monitors, and power supplies, including residual-charge hazards
- Proper disposal and environmental awareness for hardware and consumable materials
- Workspace practices that protect both the technician and the equipment
Key Takeaway
Because the 14 competencies are unweighted, an "easy" domain is worth just as much preparation as a hard one. Give Safety a dedicated study block and a few practice sets rather than assuming you already know it.
Networking and Portables
Domain 10: Basic Networking Concepts Applicable to Computer Service
The scope here is deliberately basic and service-oriented, not network engineering.
- Common network types, topologies, and media
- Network adapters, cabling, and connectors
- Basic addressing and connectivity concepts a service tech needs to verify a workstation is online
- Sharing resources and recognizing common connectivity faults
Domain 11: Portables
Laptops and similar devices have their own service realities.
- Differences between portable and desktop components, including proprietary and compact designs
- Power management, batteries, and charging behavior
- Docking, display, and input differences
- Careful disassembly and the unique challenges of replacing portable parts
Candidates from a pure desktop background often underestimate Portables, while networking-minded candidates sometimes over-study Domain 10. Match your effort to the stated scope: practical, entry-level knowledge that supports service work.
Troubleshooting, Operating Systems, and File Management
Domain 12: Troubleshooting / Preventive Maintenance / Security Measures
This domain is where the other thirteen come together.
- A logical, repeatable approach to isolating a fault
- Preventive maintenance routines that reduce failures
- Basic security measures for systems and data
- Interpreting symptoms to decide which component or setting to examine first
Domain 13: Operating Systems (Windows 7, 8, 10, 11 / Linux / Apple Mac)
The named versions are part of the competency language, so study them as listed.
- Installation, configuration, and basic administration across the Windows versions named in the requirements
- Foundational Linux and Apple Mac concepts that a service technician encounters
- Recognizing differences in interface, tools, and terminology between platforms
- Boot processes and common startup problems
Domain 14: File Management
Often overlooked because it feels like end-user knowledge.
- File systems, directory structures, and naming conventions
- File attributes, permissions, and organization
- Backup, copy, move, and recovery concepts
- Managing files across the operating systems covered in Domain 13
Sequencing Your Preparation
Generic study advice matters less than ordering your topics sensibly. A sequence that follows how the domains build on each other works well. Here is one eight-week layout, adjustable to your starting point:
Foundations
- Domain 1 (Safety) and Domain 9 (Power), since electricity and ESD underpin everything else
- Review basic electronics if you lack that background
Core Hardware
- Domains 2 through 5: assembly, motherboards and buses, processors, memory
- Pair each topic with component identification practice
Storage, Cards, and Ports
- Domains 6, 7, and 8, with emphasis on legacy and current interfaces side by side
Connectivity and Mobility
- Domain 10 (basic networking) and Domain 11 (portables)
Software Side
- Domains 13 and 14: operating systems and file management across Windows, Linux, and Mac
Integration
- Domain 12 troubleshooting scenarios that cut across every earlier domain
Timed Practice
- Full 80-question sets under a two-hour limit with a scientific calculator and scratch paper, then targeted review of weak domains
Use the CST practice test throughout rather than saving it for the end. Early practice questions reveal which domains you misjudged, and timed sets in the final week build the pacing you need for 80 questions in two hours. Our broader study guide overview and CST training resources can supplement this schedule.
Prerequisites, Pathways, and the A+ Rollover
Standalone CST does not require the Certified Electronics Technician Associate (CETa) credential. However, ETA's competency document suggests CETa or equivalent basic electronics preparation, which is sensible advice given how much of the exam touches power and electrical concepts. If your electronics foundation is thin, add extra time to Domain 9 and the fundamentals in Domain 1. For eligibility details, see our CST requirements guide.
| Pathway | What It Involves |
|---|---|
| Standalone CST | Take the exam directly; CETa not required, though basic electronics preparation is suggested |
| Journeyman path | Requires CETa and at least two years of combined training and experience |
| CompTIA A+ rollover | A valid CompTIA A+ (ce), but not lifetime A+, qualifies for the separate USD 80 CST rollover route |
The rollover is worth noting if you already hold a current A+ with continuing education. It is a distinct route with its own USD 80 fee, and a lifetime A+ does not qualify. If you are weighing the credential against your career goals, our analyses of whether the CST is worth it, the CST salary picture, and typical CST jobs can help you decide how much effort to invest.
After You Pass: Four-Year Maintenance
The certification lasts four years. Standard maintenance requires:
- The maintenance form
- 10 continuing-education contact hours per year (40 over the four-year cycle) or supervisor-completed employer verification
- USD 25 per year (USD 100 per four-year cycle)
The employer-verification option is convenient for technicians who are actively working in the field, since it can substitute for logging individual contact hours. Plan for these costs and paperwork from the start so your credential never lapses.
Frequently Asked Questions
The exam has 80 questions with a two-hour time limit. It is a proctored theory examination with no hands-on assessment. Passing requires 75%.
ETA offers one free examination retake within one year of your initial session. If you test through remote proctoring, the USD 16 proctoring fee still applies to the retake. Use your first result to identify weak domains before rescheduling.
You may bring a non-programmable scientific calculator and use scratch paper, but used scratch paper must be surrendered afterward. Photo ID is required. Notes and reference materials are not part of the permitted items listed.
No. Standalone CST does not require CETa, though the competency document suggests CETa or equivalent basic electronics preparation. The Journeyman path does require CETa plus at least two years of combined training and experience.
The 14 official competency headings are unweighted, so ETA does not publish percentages per domain. The safest approach is to build competence across all of them. Check our CST pass rate discussion and keep practicing with the CST practice exams to find your weakest areas.