A bench you can actually build, and what it costs to prove each thing

This lesson maps to no 220-1201 objective. CompTIA does not examine "build a bench", and nothing in it will be asked of you. It exists because the labs attached to objectives 1.1, 1.2, 3.1, 3.2, 3.3, 3.4, 5.1 and 5.2 all need real hardware to run on — and on this exam, unlike the others in this series, roughly half of what is examined cannot be virtualised at all. It also states the safety rules once, in one place, so that every later lab can point at them.

Why this matters

Every other course in this library starts by telling you to build a virtual machine. This one cannot, and being honest about that early is worth more than a cheerful lab guide that quietly assumes you own three computers.

Core 1 is a hardware exam. Its questions are about parts that fail physically: a power supply that sags under load, a bent pin, a cable that charges but does not carry data, a swollen cell, a drive that clicks. None of those can be simulated, and a candidate who has only read about them can usually still pass — but will answer more slowly, and will get the scenario questions wrong, because scenario questions describe symptoms rather than naming components.

So this lesson does two things. It sets out the smallest bench that lets you prove things for yourself, with honest prices and honest substitutions. And it states the safety rules once, for the whole course, so that every lab after it can point here instead of restating half of them and leaving out the half that mattered.

The lesson

Why an A+ lab is physical: the faults this exam asks about cannot be virtualised

A virtual machine has no power supply, no thermal limit you can reach, no connector to seat wrongly, and no cable. It will never show you an intermittent fault, because the hardware underneath it is not the hardware under test.

Concretely, here is what a virtual machine cannot teach you, all of which the exam asks about:

• What a machine does when the supply is failing under load but fine at idle.
• The difference between no power, no POST, and no display — three faults that present as "it does not turn on".
• Why a display works on one cable and not another that appears identical.
• What a drive sounds like when the heads are failing.
• How much force is correct when seating memory, and what "correct" feels like.

Everything in domains 2 and 4 — addressing, protocols, hypervisors, cloud models — virtualises fine. Roughly half of domains 1, 3 and 5 does not. Plan the bench around the half that does not.

The minimum bench: one working machine, a phone, a retired desktop and a multimeter

The bench that covers most of this course is smaller than people expect:

• The machine you already have. It runs the hypervisor for domain 4, it runs the network tools for domain 2, and it is the known-good reference for everything else.
• A phone. Any phone. It covers the mobile connectivity, account synchronisation and pairing work in domain 1 without buying anything.
• A retired desktop or laptop that you are allowed to open. This is the important one, and it should be a machine you do not need. It is where you seat memory, reseat a processor cooler, trace a power connector, and where you can leave the cover off for a week.
• A multimeter. The cheapest one with continuity, DC voltage and resistance is enough for everything in this course. This is the single most useful purchase on the list.
• A cheap cable tester and a few short patch leads, one of which you terminate yourself and one of which you terminate wrongly on purpose.

Optional, in rough order of usefulness: a USB-Ethernet adapter, a spare known-good power supply, a set of plastic prying tools, and a magnetic screw mat. The total is small, and most of it is reusable well beyond this exam.

What a virtual machine can and cannot stand in for, and where that boundary sits

The boundary is worth stating precisely, because the labs in this course use it to decide what each exercise is allowed to claim.

A virtual machine can stand in for:

• Operating system installation, partitioning and file systems.
• Network configuration: addressing, masks, gateways, DNS, DHCP behaviour.
• Anything about protocols, ports and name resolution.
• Hypervisor behaviour, snapshots, resource allocation, virtual networking.
• Cloud service model reasoning, which is a responsibility question rather than a technical one.

A virtual machine cannot stand in for:

• Any measurement with a meter.
• Any fault whose cause is heat, power, vibration or a connector.
• Anything about physical connectors, keying, or cable capability.
• Printers, beyond the queue and driver layer.
• The feel of an installation step, which is genuinely part of the job.

Where a lab in this course is limited to the first list, it says so. Where it needs the second, it says what it needs before it starts, so you find out before you are halfway through.

Sourcing parts from e-waste, returns and old estates without spending money

Almost every part in domain 3 can be obtained for nothing if you ask the right people:

• Workplace disposal. Organisations retire hardware constantly and usually pay to dispose of it. A written request to take a decommissioned desktop is routinely granted, once the disks have been handled by whoever is responsible for them. Never take storage media without explicit permission — that is a data question, not a hardware one.
• Recycling centres and e-waste events. Many will let you take items, and the parts you want — power supplies, memory, cables, old drives — are the ones nobody else does.
• Friends and family machines that died. A machine that "just stopped working" is a free fault to diagnose, and it comes with a real symptom description, which is the part textbooks cannot provide.
• Cables, always. Take every cable offered. Half this exam is connectors, and a box of assorted leads is the cheapest revision aid available.

Two rules: know what you are taking before you take it, and wipe or destroy storage properly rather than assuming a delete is enough. The operational procedures that govern that belong to Core 2, but the obligation starts the moment a disk is in your hand.

The safety rules this course assumes from here: mains, capacitors, cells and static

These are stated once and referenced everywhere after. They are not optional and they are examinable in their own right.

• Mains voltage is the one that kills. You do not open a power supply. The capacitors inside hold a lethal charge after disconnection, and there is nothing user-serviceable behind the cover. Testing a supply is done at its output connectors, from outside the case. Lesson 43 covers how.
• Cathode ray displays and laser printer power supplies carry the same warning for the same reason, and both appear in this exam's scope.
• Lithium cells are a fire risk, not a shock risk. Do not puncture, compress or charge a damaged pack. Handle with non-conductive tools, store and dispose of damaged cells according to local rules.
• Static damages components silently. The failure usually arrives weeks later, which makes it hard to learn from. An anti-static strap connected to an unpainted chassis point is the standard control; working on a conductive mat, avoiding carpet, and handling boards by the edges are the free ones. The one exception is a power supply — never wear a grounded strap while working near mains.
• Power down and disconnect before opening anything, and on a laptop that means the internal battery as well, as lesson 1 set out.
• Lift with your legs, and get help with anything heavy. Printers and display equipment are the two things on this exam that regularly injure people, and neither is exciting enough to be careful about by instinct.

Where a lab in this course involves any of the above, its Environment section says so explicitly, and a lab that asks you to do something these rules forbid is a lab with a mistake in it.