Recognize
Identify common desktop components and connectors by shape, function, labels, and standards rather than by brand or color.
CompTIA A+ • Mission 03
Motherboards, Connectors & PC Hardware
Use one training desktop to learn safe disassembly and another set of compatible parts to practice assembly. The goal is not to memorize one computer—it is to recognize the common standards, functions, connectors, and compatibility checks that transfer to many PCs.
A+ alignment • Module 2
What you are learning in this mission
This mission reinforces cable types and connectors, motherboard installation/configuration, legacy connections, electrical/ESD safety, form factors, storage/expansion connectors, headers, power connections, display interfaces, and common expansion devices.
Compare
Compare desktops with laptops, phones/tablets, and Raspberry Pi systems. The jobs are similar, but packaging, power, cooling, expansion, and serviceability differ.
Disassemble
Document a complete training PC, remove parts in a safe order, identify power/data paths, and preserve screws/cables for reassembly.
Build
Plan and begin a PC assembly only after checking form factor, CPU/socket, memory, power, storage, expansion, cooling, and case compatibility.
Technician rule: Do not memorize where a connector appears on one motherboard. A connector may be on a different edge or in a different orientation on another board. Learn what it is, what it does, what plugs into it, and how to verify it.
Many manufacturers • common standards
Expect variation without losing the fundamentals.
A computer may come from a major OEM, a local/custom builder, a school or business deployment, or a home build. The motherboard, memory, storage, power supply, case, cooling, and expansion devices can also come from different manufacturers and may be manufactured or assembled in different countries.
Common standards help
ATX/microATX/mini-ITX, PCIe, SATA, M.2, USB, HDMI/DisplayPort, DIMM, Ethernet, and common power connections give technicians a shared vocabulary.
But implementations differ
Some systems use proprietary motherboard shapes, power connections, front-panel wiring, cooling assemblies, drive mounts, or service procedures. Always inspect and verify before assuming.
Country of manufacture is not a compatibility specification. Compatibility comes from the technical requirements: form factor, electrical connection, interface, socket, protocol, dimensions, firmware support, and documentation.
Component field guide
Learn the common parts you can carry to almost any PC.
| Part / connection | Desktop PC | Laptop / mobile comparison | What to verify |
|---|---|---|---|
| Motherboard / system board | Main board connecting CPU, RAM, storage, expansion, power, and I/O. | Laptops and phones also have system boards, but many parts are more integrated or soldered. | Form factor, mounting, ports, socket/CPU support, RAM, storage, power, case connections. |
| CPU / processor | Often a replaceable socketed Intel/AMD-style x86-64 processor in serviceable desktops. | Many laptops use soldered processors; phones/tablets commonly use Arm-based SoCs. Pi 5 uses a soldered Arm-based SoC. | Socket, chipset/firmware support, cooler, thermal solution, architecture. |
| RAM | Usually removable full-size DIMMs. | Serviceable laptops may use SO-DIMMs; many thin laptops, phones, tablets, and SBCs use soldered low-power memory. | DDR generation, capacity, speed/support, slot population, soldered vs. replaceable. |
| Storage | SATA HDD/SSD and M.2 NVMe are common. | Laptops commonly use M.2 NVMe; phones/tablets often use soldered flash; Pi commonly uses microSD or supported USB/PCIe storage. | Interface, form factor, capacity, mounting, boot support, available ports/lanes. |
| Power | Internal PSU supplies motherboard, CPU, GPU, drives, and fans. | Laptops use an external adapter plus battery; phones/tablets use a charger/battery system; Pi uses external DC power. | Connector type, voltage/power requirements, wattage, PSU capacity, proprietary vs. standard connectors. |
| Expansion | PCIe slots may accept GPU, NIC, capture, storage, or other cards. | Laptops rely more on M.2 modules, USB-C/Thunderbolt, docks, and integrated devices; phones/tablets have very limited internal expansion. | Slot type/lane width, physical clearance, power, drivers, system support. |
| Display | HDMI/DisplayPort common; older systems may expose DVI/VGA. | Laptop/tablet/phone displays are built in, with internal panel connectors; external outputs vary by device. | Connector, cable capability, resolution/refresh support, GPU/display support. |
| Cooling | Heat sinks, fans, case airflow; sometimes liquid cooling. | Laptops use compact fans/heat pipes; phones/tablets rely heavily on passive heat spreading and thermal management. | Clearance, mounting, fan header, airflow direction, thermal interface, dust. |
Hands-on Lab A
Disassemble a training PC like a technician—not like a scavenger hunt.
An older working or non-working desktop is useful because it may expose optical drives, SATA cabling, larger drive bays, legacy display connectors, expansion cards, and other hardware you may still encounter.
Power down and isolate
Shut the system down. Disconnect external power and peripherals. Follow appropriate ESD precautions. Never open a PSU enclosure.
Document the outside
Identify power, USB, network, audio, display, optical/removable media, vents, and expansion openings. Photograph or sketch what you see.
Open and photograph BEFORE unplugging
Take clear photos of cable routing, motherboard connections, drive connections, front-panel wiring, fans, and expansion cards. These become reassembly evidence.
Create a parts/screw system
Use labeled cups, bags, or a parts tray. Keep screws with the component or location they came from. Avoid mixing motherboard, drive, case, and expansion-card screws.
Trace power vs. data
For each major component, identify which connection supplies power and which carries data. Some interfaces can carry both power and data; document the difference.
Remove easy-access components first
Depending on the system: expansion cards, storage/optical drives, and removable cables may come out before the motherboard. Do not force clips, latches, or keyed connectors.
Remove RAM and cooling carefully
Release memory latches correctly. If removing a CPU cooler, follow the hardware's procedure; thermal material can make an old cooler feel stuck. Do not pry aggressively.
Motherboard last
Verify all cables/cards are free, locate every motherboard screw, support the board, then lift it without scraping the underside across metal standoffs.
Inventory what you learned
Name each major part, identify its connector(s), describe its function, and classify it as current/common, older/legacy, or system-specific.
Before assembly
Compatibility first. Installation second.
Case ↔ motherboard
Confirm supported motherboard form factor and mounting-hole/standoff pattern. Check rear I/O opening and expansion-slot alignment.
CPU ↔ socket ↔ firmware
A CPU physically fitting is not enough. Verify the exact socket, chipset/platform support, firmware/UEFI requirements, and cooler compatibility.
RAM ↔ motherboard
Verify DDR generation, supported capacity/speed, module type, and recommended slot population. DDR generations are physically keyed differently.
Storage ↔ interface
Check SATA versus M.2, and for M.2 determine whether the slot supports the drive's interface/protocol and physical length.
PSU ↔ system
Verify physical PSU form factor, required motherboard/CPU/GPU/storage connectors, total power needs, and any proprietary system connections.
GPU / expansion ↔ case
Verify PCIe slot support, card length/height/thickness, power connectors, cooling clearance, and available expansion slots.
Do not build by logo. A case, motherboard, CPU, memory kit, PSU, or GPU do not need matching manufacturer names. They need compatible standards and specifications.
Interactive compatibility lab
Build a system by compatibility—not by brand.
Start with a platform/case. Each choice filters the next list so you can practice the same questions a technician asks before buying or installing parts. The catalog is intentionally generic: it teaches standards, sockets, form factors, interfaces, and power requirements rather than particular manufacturers.
Case support determines which motherboard/system-board form factors physically fit.
Desktop boards must fit the case. Pi uses an integrated single-board computer instead.
Desktop CPU compatibility depends on socket/platform support. Pi 5's processor is soldered to the board.
Match memory generation/type. Desktop DIMMs are not interchangeable with laptop SO-DIMMs or soldered LPDDR.
Check interface and physical support: SATA, M.2 NVMe, microSD, USB, or supported PCIe storage.
Dedicated GPUs add slot, clearance, cooling, and power requirements. Integrated graphics may need no separate card.
Verify socket mounting, thermal capacity, case clearance, fan headers, and airflow.
Start with a platform
Your compatibility report will appear here.
—Estimated selected load
—Power recommendation
—Form factor / power type
- Choose the case/platform to begin filtering compatible parts.
Training note: A wattage calculator is a planning tool, not a substitute for component documentation. Real builds must also verify connector count/type, transient loads, PSU quality, efficiency, physical size, and manufacturer specifications.
A+ connection: This activity practices form factors, motherboard/CPU compatibility, RAM generations, storage interfaces, PCIe expansion, cooling, power requirements, and troubleshooting logic. A part can be electrically compatible but still fail a physical-clearance, firmware, connector, or power check.
Hands-on Lab B
Build with a repeatable technician workflow.
Read the manuals and inspect every part
Before installation, identify motherboard form factor, socket, DIMM slots, M.2/SATA, PCIe, main power, CPU power, fan headers, front-panel header, USB/audio headers, rear I/O, and case mounting points.
Prepare the case and standoffs
Remove both side panels when possible. Match standoffs to motherboard mounting holes. Remove any standoff that does not correspond to a motherboard hole.
Install the I/O shield if the board uses a separate one
Some boards have an integrated shield; others use a separate shield. Install the correct shield before the motherboard if required.
Pre-install accessible components
When appropriate, install CPU, cooler mounting hardware, RAM, and M.2 storage before the motherboard goes into the case. This can provide better access and reduce awkward pressure on the installed board.
CPU: align—never force
Use the socket's alignment indicator/notches and the manufacturer's procedure. If orientation is correct, the CPU should seat without being pushed into place.
RAM: verify the notch and recommended slots
Open the latches as designed, align the module notch, apply even pressure, and verify the module is fully seated. Use the board documentation for preferred slots when installing fewer modules than available slots.
M.2: confirm interface and length
Insert the module at the specified angle, secure it with the correct mounting hardware, and use a heat spreader/thermal pad only as instructed.
Lower the motherboard onto the standoffs
Align rear I/O and mounting holes. Start screws loosely, confirm alignment, then secure evenly. Tighten until secure—not excessively.
Connect power correctly
Identify the motherboard's main ATX power and the CPU/EPS power connection. Do not confuse CPU/EPS and PCIe/GPU power just because connectors may look similar.
Connect case headers using the diagram
Front power/reset switches, LEDs, USB, audio, and fans may use separate headers. Front-panel layouts vary—use motherboard labels/manuals rather than guessing.
Install drives and expansion cards
Mount storage securely, connect required power/data, and install PCIe cards into the correct slot. Verify latch engagement, case clearance, and supplemental power if required.
Manage cables for serviceability and airflow
Keep cables away from fan blades, avoid excessive tension, and route them so future troubleshooting or upgrades do not require dismantling the entire computer.
Perform a pre-power inspection
Check motherboard/CPU power, RAM seating, storage, fan connections, GPU power, front-panel wiring, loose screws, tools, and cables touching fans. Do not rush this step.
First power: observe before celebrating
Watch for fans, LEDs/diagnostic indicators, POST behavior, display output, unusual sounds, smells, or shutdowns. If it fails, stop and troubleshoot from evidence rather than repeatedly power-cycling.
The simplest build rule: If a part or connector does not fit easily, STOP. Check orientation, keying, compatibility, and documentation before applying more force.
Connector thinking
Ask three questions every time you touch a cable.
1. What is it?
Name the connector or header. Use the shape, key, latch, pin arrangement, board label, and documentation.
2. What does it connect?
Motherboard? CPU? drive? GPU? fan? front panel? external peripheral? display? network?
3. What does it carry?
Power, data, signal, or a combination? Knowing this speeds up troubleshooting when something is not detected or not receiving power.
4. Is it current or legacy?
A technician may still encounter SATA, optical drives, VGA/DVI, serial connections, older PCI hardware, or adapters. Recognize them even if your new build does not use them.
Mission checks
Practice the decisions technicians actually make.
Progress: 0 / 8 correct
Check 1
You open a desktop you have never worked on before. What should you do BEFORE disconnecting internal cables?
Documenting the original state gives you evidence for reassembly and troubleshooting. Technicians should not rely on memory when layouts and proprietary connections can vary.
Check 2
What is the BEST reason to verify motherboard standoff locations before installing a board?
Only use standoffs that line up with motherboard mounting holes. Extra metal under the board can create an electrical short.
Check 3
A power connector will not seat easily. What should you do FIRST?
Most PC connectors are keyed. Resistance is a clue to stop and recheck orientation or compatibility instead of forcing the connection.
Check 4
Which statement is most accurate about a laptop memory upgrade?
SO-DIMMs are common in serviceable laptops, but many thin/mobile systems use soldered memory. The technician should verify the exact model specifications.
Check 5
You are replacing a motherboard in an unfamiliar desktop. Which information matters MOST before installation?
Compatibility is determined by technical standards and the system design—not matching logos or country of manufacture.
Check 6
Which connection is intended primarily to carry DATA to a SATA storage drive?
A typical SATA drive uses separate SATA data and SATA power connections. Knowing which connection carries data versus power is important for both installation and troubleshooting.
Check 7
A desktop has an optical drive and large internal drive bays that newer systems may not use. What is the BEST technician conclusion?
Older PCs are useful training systems because they show how standards and designs evolve. A+ learners need to recognize both common current technologies and older interfaces they may encounter.
Check 8
Which statement BEST describes how different manufacturers affect PC service work?
A technician learns the standard first, then verifies how the specific system implements it. Some systems use proprietary designs even when they look similar to standard PCs.
A+ notebook build
Create an “Anatomy of a PC” reference you will actually study.
Your notebook can help you identify and compare hardware without becoming a handwritten copy of this page. Use the ideas below as suggestions; choose the formats that help you study best.
Mission 03 notebook suggestions
Suggested idea 1 — Motherboard Field Map
- CPU socket
- DIMM slots
- PCIe x16 / smaller PCIe slots
- M.2
- SATA
- 24-pin main power
- CPU/EPS power
- fan headers
- front-panel header
- USB/audio headers
- rear I/O
For each major connection, add: what connects here • what it carries • one troubleshooting clue.
Suggested idea 2 — Desktop / Laptop / Phone-Tablet / Raspberry Pi comparison
- Processor: socketed vs. soldered; x86-64 vs. Arm examples
- Memory: DIMM vs. SO-DIMM vs. soldered LPDDR
- Storage: SATA/M.2 vs. mobile flash vs. microSD/PCIe
- Power: desktop PSU vs. laptop adapter+battery vs. phone/tablet battery vs. Pi external DC
- Expansion/cooling/display/networking differences
Suggested idea 3 — Build/Disassembly Evidence
- One before photo/sketch
- One labeled internal photo/sketch
- Three connectors you physically handled
- One older/legacy component you found
- One compatibility check you made before installation
- One mistake/question you want Future You to remember
Build success tips
Small habits prevent big problems.
Use your phone as documentation
Take photos before disassembly, before hiding cables, and before closing the case. Photos make troubleshooting and reassembly easier.
Never mix screws casually
A wrong screw can damage a component or fail to secure it. Label parts and mounting hardware as you work.
Keep packaging until POST
Boxes, anti-static bags, socket covers, screws, adapters, and manuals may be needed if a part must be exchanged or rechecked.
Do not cable-manage too early
Route neatly, but avoid fully tightening/tie-wrapping everything until the system successfully POSTs and major devices are detected.
Test one change at a time
If troubleshooting, avoid changing five things simultaneously. A controlled test makes it easier to know what actually fixed the issue.
Check the simple things first
Power switch, PSU switch, display input, motherboard power, CPU power, RAM seating, GPU power/display connection, and front-panel header mistakes are common first-build issues.
Certification connection: The instructor-provided A+ Module 2 material covers cables/connectors, USB, display interfaces, SATA/eSATA, motherboard functions, ESD, CPU/memory connectors, M.2, PCI/PCIe, form factors, motherboard installation, headers/power connectors, video/capture/sound/network cards, and legacy interfaces such as DVI/VGA/serial. Mission 03 turns those topics into identification, compatibility, disassembly, assembly, and troubleshooting practice.