Salvage

Under martial law in Poland in the early 1980s, Solidarity's underground radio ran on transmitters its own engineers built. Its broadcasters boasted on air that almost 90 percent of the equipment used by official radio and television came from abroad, a supply the state controlled, while the underground sourced its own from ordinary domestic parts.6 A forensic expert at one of the trials testified that a transmitter came down to a store-bought audio cassette recorder, duralumin pipes for the antenna, and a length of shielded cable, with only the single transistor hard to find, for no more than a few tens of thousands of złotys.6 Keeping a set basic and cheap was also a necessity: the police learned to triangulate a transmitter and seize it, so a set had to be one you could trigger, leave, and afford to lose.6

A manufacturer that sells a durable good to a captive market has a standing reason to shorten the life of what it sells, so that the customer has to buy again. The economist Jeremy Bulow set out the theory: planned obsolescence is “the production of goods with uneconomically short useful lives so that customers will have to make repeat purchases.”24 Apple fingerprints individual components with a serial number and pairs them to one phone, so a genuine battery, screen, or camera moved into another device loses function (the battery reports it cannot be verified, the screen disables Face ID) unless the swap is signed off through the company’s own software. The count of iPhone parts locked this way rose from two in 2015 to nine by 2020.25 Under right-to-repair pressure, Apple began in 2024 to let some genuine used parts be reused through its own calibration flow, though aftermarket parts stay locked.25 John Deere handed the diagnostic software that authorizes a repair to its own dealers alone, until the Federal Trade Commission, Illinois, and Minnesota sued in January 2025, with three more states joining before a July 2026 settlement forced the company to give farmers and independent shops the same tools for ten years.26 A printer maker ships a firmware update that makes the machine reject a refilled cartridge as damaged or missing.27

The European Union’s Right to Repair Directive bars a maker from using hardware or software to impede a repair, but only where the block is not “justified by … the protection of intellectual property rights,” a carve-out its critics read as a loophole wide enough to swallow the rule.28 In the United States, makers build a digital lock into a device to block repair, and breaking it was once a crime under copyright law. That law now lets you break the lock to fix your own device, yet still forbids making or sharing the tool that does the breaking.29

Sourcing from what a fight leaves behind is old doctrine. “Since ancient times,” one study of undergrounds observes, “irregular forces have relied on battlefield recovery”; modern insurgencies “likewise seek to obtain vehicles, communications equipment, food, medical supplies, and other items from their clashes with government military and police forces.”30 Italian factory workers slipped radios out of the plants they worked in to supply the wartime resistance; the Polish Home Army hid a workshop above a welding shop so the noise of its machines would pass for the shop’s.30 Salvage runs the same logic on discarded electronics, no clash required.

You source through three channels, ranked by how much each one exposes you. E-waste comes first: discarded electronics from the curb, the thrift store, and the recycler, all of it free, anonymous, and tied to no one. The cash economy exposes you a little more but still leaves no paper trail, covering pawn shops, junkyards, flea markets, and estate sales. Commercial channels expose you the most, since a card or an account puts your name on the purchase. You use them last, only for what you cannot salvage or find, and then only through the hardened stack you built in Module 00, paying privately.5

The module in one picture: three channels, ranked by exposure. You reach for the lowest-exposure channel that can supply the part.

A dead inkjet printer on the curb holds a stepper motor, a DC motor, and the rollers and gears of an actuator; a dead laptop pack holds a row of 18650 lithium cells. Open a discarded device and you find motors, switches, magnets, gears, shafts, pulleys, belts, lenses, and lots of screws.1

Resistors are too cheap to bother pulling.2 Keep motors of any kind, connectors, hookup wire, seven-segment LED displays, loudspeakers, switches, large transistors and diodes, large or unusual capacitors, and screws, nuts, and bolts.2 Do not desolder what you can cut: snipping parts free with wire cutters is fastest, as long as the leads left behind are long enough to use.2

The cash economy, the second channel from Unit 01, takes cash at pawn shops, junkyards, flea markets, estate sales, and person-to-person sales, and cash, unlike a card or an account, leaves little on the record tying a purchase to you.4

Before you go out, make a list of the parts you are after.3 The list points you at the places most likely to have them, tells you which finds matter most on a given trip, and settles in advance what you leave for next time.3

Look a place over before you commit to it, in daylight and again near the time you would actually go, so you can pick the best moment and see who and what moves through.3 Learn its rhythm: the outlet bins turn over on a schedule, the curb fills the night before collection, a campus empties at the end of a term. Go when it is full and few people are around. Watch for the site's own hazards too (unsound floors, roofs, and walls, or a tight space) and plan for them before you move.3 One rule never bends: always have a way out, and a plan to leave if something is wrong.3

1. The bit driver and its security bits. Pentalobe alone comes in three sizes you will meet, P2 on a phone and P5 or P6 on a laptop, and it is a five-point head, not the six of a Torx, so the two do not interchange.31 One trap hides in a screw that looks like plain Phillips: a Japanese JIS head has square corners in its cross where a Phillips has tapered ones, so a Phillips driver cams out and chews the head, and the two are not always interchangeable.31 Let the screw choose the bit: if a driver slips in the head, it is the wrong bit or the wrong size, and every slip costs you the screw. Stop and swap before the head rounds.
2. The spudger and the picks. Work a clipped case along the seam clip by clip, not all at once: forcing one point is how tabs snap.15
3. The heat pouch. Heat first, pry second: a glued case gives only once the adhesive has softened, and prying it cold is how screens crack.15
4. The stripped screw, in order. When a head rounds and the bit just spins, climb a ladder and stop at the first rung that holds: lay a wide rubber band over the head and turn through it, so the rubber fills the stripped recess and grips; if that fails, a screw extractor, a reverse-cut bit that bites as it turns counterclockwise.39 The rotary tool is the last rung: cut a fresh slot across the head and back it out with the flathead.139 That same tool opens a molded case with no fasteners at all, but never for exploring.1

The heads you will meet, drawn to shape. Let the screw choose the bit: a driver that slips is the wrong one, and a Phillips forced into a JIS or a Torx head strips it.

The tool for those heads: one cheap set gathers a range of tamper-resistant bits in a single holder. A precision driver and a set like this opens almost anything you will meet. Photo: Junkyardsparkle, public domain.

Eight rules apply to every teardown.1

1. Cut off any power cords. Snip the cord and bend the prongs outward, so the plug can never go back into an outlet.1
2. Protect your eyes. Springs jump, bits of metal and plastic fly, and tools slip, so wear glasses or, better, safety goggles before the first screw comes out.1
3. Pry away from you. Most teardown injuries happen when a screwdriver under hard pressure slips. Keep the blade pointed away from your hand and your body, so a slip travels away from you.1
4. Do not force the device apart. No hammering and no sawing it open. The person who assembled the device did not force the parts into place, so you should not need to force them out; if you are stuck, look for the fastener or tab you have missed and try a different approach.1
5. Watch out for capacitors. Most are harmless, but some hold enough charge to knock you to the floor, and the worst can kill.1
6. Lefty loosens. Almost every screw backs out counterclockwise.1
7. Wash your hands. The materials inside electronics do not belong in your body. Wash your hands when you finish, and do not eat or drink while you work.1
8. If you don't know what it is, don't cut into it. A rotary tool is for a case you have chosen to open, never for exploring. Cutting blind into a sealed component can release material you do not want in the air.1

1. Discharge before you touch. With the device unplugged and the cord already cut off, bend the legs of a 100-ohm resistor to match the span of the capacitor's two terminals. For the low-voltage capacitors this module opens, 100 ohms is fine; a higher-voltage capacitor wants a larger resistor, a kilohm or more, to soften the bleed. A higher-wattage resistor is better; an overloaded resistor breaks, but not as dangerously as a capacitor discharged the wrong way.2
2. Hold the resistor by its body in the teeth of a pair of pliers, gripping the insulated handles, and press a resistor leg to each terminal for a few seconds, so the charge drains through the resistor instead of across an arc.2
3. Set your multimeter to its highest voltage range and read across the terminals to confirm the capacitor is down to a safe level: under 50 volts to handle it at all, and ideally a couple of volts or less before your hands go near the board.2

Only a very small capacitor should ever be discharged by shorting its leads with a screwdriver; a large one at high voltage can dump a huge charge in a fraction of a second, melting the tip and flinging molten metal.2

A flat-panel TV or monitor has no cathode-ray tube, so it holds none of the years-long CRT charge the warning above flags. What it does have is a switch-mode power supply board, the same class the discharge drill is for,2 and a backlight: mercury is used in LCD screens and monitors,17 and in an older panel the backlight is a cold-cathode fluorescent lamp, a thin glass tube filled with mercury vapor, so you never crush or break it.21

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The same rig as a schematic: the resistor bleeds the charge; the meter verifies about 50 V or less before your fingers go in. Drawn in KiCad.

Screws alone rarely open a modern case. Keep the screws in order as they come out, laid on the bench in the pattern they held or pushed into a scrap of foam, because they are rarely all one length.2 Photograph any step you are not sure you can reverse.2

1. Snap-fit clips. They run along the seam. Find them with a pick and release them one at a time, and a clip about to break resists differently from one about to let go.
2. Plastic rivets. Lever them off with a flathead worked under the plate they hold.1
3. Adhesive. Heat first, then a slow pry, as in Unit 03, or a solvent remover run along the seam and given two or three minutes to soften the bond before you lift.32
4. Parts closed for good. A black epoxy blob over a chip is a bare die sealed under epoxy to protect it, built to last the life of the device;1 a part potted solid in resin is shut the same way. Neither comes out intact, so you take what surrounds it and leave it.

A salvaged board gives up its switches, connectors, and chips only to a desoldering tool. Soldering and desoldering are a bench skill of their own, with a standalone trainer in the series LABS; run it before your first board-level pull.

A pulled board carries parts whose numbers mean nothing to you. A mass-produced device documents itself, though, in three places you can reach: its regulatory filing, its service literature, and the datasheets of the chips on it.

The regulatory filing. Anything that transmits radio (a router, a phone, a wireless mouse, a remote) and is sold in the United States carries an FCC ID printed on its label, and that ID opens a public file. The ID is two parts: a grantee code the FCC assigns to the maker, and a product code the maker assigns to the device.33 Type it into the FCC’s Equipment Authorization Search, or a mirror such as fccid.io, and the file opens.

The file always carries the label and its location on the device, the radio test report, and the exposure data. It usually carries external and internal photographs and the user manual, held back only for a 180-day window and then released.33 But the maker may withhold for good the very exhibits a salvager most wants: the schematic, the block diagram, the written description of how the thing works, and the parts list.33 Only a device printed with an FCC ID string has a file; the FCC logo mark alone is not an ID and opens nothing.33

Service manuals and datasheets. Many appliances and older consumer devices have a service manual the maker wrote for its own repair techs, with exploded parts diagrams and often a full schematic; search the exact model number with the words service manual. For a chip you have named, its datasheet is the authority: it gives the pin assignments, the recommended operating conditions, and the absolute maximum ratings. The two are not the same: the recommended operating conditions are the range where the part is guaranteed to work; the absolute maximum ratings must not be exceeded even for a moment, or the part can be damaged for good.40 A salvaged part earns the conservative one. A datasheet assumes you already know the device, but it reliably tells you what each pin does, the power it needs, the outer limits of its operation, and often an example circuit.37

Reading the board itself. The letters and number printed beside each part, its reference designator, are a standard code of one or two letters and a number.34 They are how a spot on the board maps to a line on a schematic.

A real board: the silkscreen letter beside each part names its kind. Here, L a coil, R a resistor, C a capacitor, D a diode, and U an integrated circuit. Photo: And1mu, Wikimedia Commons, CC BY-SA 4.0.

Naming a chip. An integrated circuit carries a few lines on its top: the maker’s logo, the part number, and a date code in the form YYWW, two digits of year and two of week.35 The part number is what you feed a datasheet search. Find pin 1 first, marked by a notch or a dot, with the pins counting up counterclockwise from it; the positive supply pin is labeled VCC, VDD, or V+, and ground is GND, VEE, VSS, or V−.37

A real chip on a salvaged board: the top lines decode into the maker’s logo, the part number (25Q128FVIQ, the string you search), and a YYWW date code (1645 = 2016, week 45); the notch marks pin 1, and even the tiny resistor array beside it carries a value code (102 = 1 kΩ). Photo: Tobias Maier, Wikimedia Commons, CC BY-SA 3.0.

The smallest surface-mount parts are too small for a full number and carry a two- or three-character code instead. The same code means different parts in different package shapes, so you read the code against the package and a code book, never on its own.36 Some markings lead nowhere: a house-numbered or sanded chip carries a number that resolves only to the maker’s private catalog. When the marking is a dead end, you fall back on testing the part by how it behaves.

A part pulled from discarded electronics may be dead itself, so you test every component before it goes in a build. Your tools are the multimeter from Module 02, plus two 9-volt batteries and some alligator clip leads.1

1. Motor. Set the meter to ohms and read across the two tabs, then turn the shaft by hand and read again. A small DC motor reads a low resistance that changes as the shaft turns, roughly 0.5 to 10 ohms, because the commutator segments switch under the brushes as it rotates.19
2. A motor that reads open (OL) at every shaft position has a broken armature winding; discard it.19
3. Clip an alligator lead to each tab and touch the free ends to a 9-volt battery, and the shaft should spin, which confirms the winding, the brushes, and the gear train together.1 Hold it only a second or two, since 9 volts is more than a small motor was built for.

The test: two alligator leads run from a 9-volt battery to the motor's tabs, and the shaft turns if the motor and its gear train are good. Photo: Unscrewed (Sobey).

The motor test as a schematic: one loop, battery to motor. A good motor spins; keep the touch brief. Drawn in KiCad.

1. Switch. A good switch's contacts read a very low resistance when they are closed and open when they are not,20 so you test one directly in continuity mode. Set the meter to continuity and clip a lead to each contact.
2. Work the switch. It should give a tone, a near-zero reading, when you press it closed, and fall silent, reading OL, when you release it.
3. A switch that never gives a tone has a contact that will not close; one that never falls silent has contacts stuck closed. Either way, discard it.

1. Stepper. Set the meter to resistance; a stepper has no obvious plus and minus, so you find its coils by reading them.
2. Probe every pair of wires: two on the same coil read a finite resistance; two on different coils read open.11
3. Count by the reading. A four-wire stepper is bipolar: two coil pairs, no center tap. A five- or six-wire stepper has center taps, where a tap reads a lower resistance to either coil end, which is how you find the common wire.11

What the probing maps out: two center-tapped coils. End to end reads the full winding, the tap reads about half to either end, and different coils never connect. Drawn in KiCad.

The silver cylinder is a stepper motor, identified by its fan of wires: a plain DC motor has two, a servo three, and a stepper four, five, or six. Photo: Unscrewed (Sobey).

A fuse is just a wire designed to burn out when the current through it gets too high, and in a clear-bodied fuse you can see that the wire inside has broken.2

1. Fuse. Pull the fuse from its holder.
2. Set the meter to continuity and put a probe on each end cap. A good fuse is an unbroken wire, so it gives a tone and reads near zero; a blown fuse is an open wire, so it stays silent and reads OL.2
3. If nothing else looks wrong, fit a replacement and try it. But if the new fuse blows at once, do not fit another: the device has a fault drawing too much current, and you find that before you spend another fuse.2

A fuse on the continuity range: the meter reads a closed circuit through a good fuse. Photo: Hacking Electronics (Monk).

1. Battery. Do not trust the resting voltage; the reading from a battery that is not powering anything can be misleading.2
2. For a truer reading, clip a resistor across the terminals as a dummy load—about 10 Ω for a 1.5 V cell, 100 Ω for a 9 V battery—and read the voltage under that load.2
3. Apply the threshold: a 1.5 V cell (AA or AAA) reading under 1.2 V, or a 9 V battery reading under 8 V, is probably dead.2

These are the disposable-chemistry numbers. Lithium cells are the exception flagged in Unit 02: a swollen or damaged one you leave alone.

A 9-volt battery under a 100 Ω dummy load reads 8.62 V: above the 8 V discard line, so it stays. Photo: Hacking Electronics (Monk).

The dummy-load test as a schematic: the resistor makes the battery work; the meter reads the truth. Drawn in KiCad.

1. Diode. Set the meter to diode test. A good silicon diode reads a forward drop of about 0.5 to 0.8 volts one way and OL the other.10 A diode that reads OL both ways is open; one that reads roughly the same drop both ways, near 0.4 volts, is shorted. Either way, discard it. A bridge rectifier is four diodes in one block, so you test each of the four the same way.
2. Transistor. A bipolar transistor behaves like two diodes that share the base leg. Set the meter to diode test, hold the red lead on the base, and touch the black lead to each of the other two legs in turn: an NPN reads a forward drop of roughly 0.5 to 0.8 volts on both, because the base is the anode of both junctions.41 Reverse the leads for a PNP. Both junctions reading open, or either reading a dead short, condemns the part. A MOSFET carries a body diode between two of its legs, and the same diode test finds it, a drop one way and OL the other.42

The diode test: the meter’s diode range pushes a small current through and reads the drop, about 0.5–0.8 V forward and OL reversed. Drawn in KiCad.

Why the diode test works on a transistor: an NPN is two diodes that share the base. Test each junction, red lead on the base. Drawn in KiCad.

The rest of what you pull reads the same way, on the resistance and diode ranges you learned in Module 02: a good coil or winding reads low but not zero, a dead short reads zero, and an open reads OL.

This section is general information, not legal advice, and the rules vary by state and change often, so you check your own jurisdiction.

Curbside trash. In California v. Greenwood, the Supreme Court held that the Fourth Amendment does not stop police from searching or seizing garbage left for collection outside a home's curtilage, since trash bags at the curb are exposed to animals, children, scavengers, snoops, and anyone else walking by.7 That is a limit on police searches, not a right for anyone else to take the trash, and the Court noted that states may set stricter limits of their own under their own law, which several do.7

What "abandoned" means. Throwing a thing out is not the same as abandoning it in law. Abandoned property is personal property an owner has intentionally given up all rights to and control over, which takes both the act of discarding it and the intent to give it up, and courts decide case by case whether both happened.13 Only movable property can be abandoned this way; real property cannot, so land and buildings are never fair game just because they sit empty.13 Curbside trash on collection day is the easy case, act and intent both plain. A working device left in a hallway, or goods inside a fenced lot, is the hard case, where the intent to give them up is exactly what is in doubt. On top of that sits a patchwork of state trespass and theft law and local waste-ownership rules, so the same pull can be lawful on one street and an offense on the next.

Trespass and ownership. What actually makes taking discarded goods illegal is usually one of two things. The first is trespass: entering posted or fenced private property, or property enclosed specifically to keep intruders out, which is what a locked dumpster enclosure is.8 The second is a local law that vests ownership of set-out waste in the city or its hauler; in California, for example, once recyclables are placed for collection, they legally belong to the authorized recycling agent, and removing them without authorization is an offense.8 This is the layer that most often turns dumpster diving into a crime, and it is entirely local.

Pull-and-haul yards. The way to salvage with none of this ambiguity is to pay for the right. Self-service yards let you walk in, pull parts off the stock with your own tools, and carry them out for a fee, and your standing to be there is a contract you agree to at the gate, not a guess about whether the goods were abandoned. The terms are routine: a small admission fee, cash or a major card, a minimum age of sixteen with a photo ID sometimes required, and a signed waiver before you enter the yard.14 Because the whole transaction is an authorized retail purchase, it sits in a different legal box from taking discarded goods; the only footprint is the ordinary one of any in-person buy, that you were there, on camera, and paid.

Scrap and e-waste. Selling salvage runs into scrap-dealer law. States require dealers to record each transaction, and California's statute is typical, demanding a description of each item bought or sold, including its type, weight, identifying marks, and serial numbers; the seller's ID; a statement of how they came to own it; and, since a 2026 amendment, the time of the transaction, the amount paid, and the employee who handled it.9 Catalytic converters and copper carry extra rules, and these change often. On disposal, many states ban electronics and batteries from landfills, and the EPA is clear that lithium, coin, and button-cell batteries do not belong in the trash, so you recycle cells rather than bin them.9

The clear path. The pulls with no ambiguity are the ones this module leans on: your own discarded electronics, curbside items on collection day, give-and-ask networks like Buy Nothing and Freecycle, repair cafes and university or corporate surplus sales, and the pull-and-haul yards where you pay for the right. You stop at the ambiguous ones (a fenced lot, a locked dumpster enclosure, a working device left in a shared hallway) because that is exactly where a free part becomes trespass or theft. When in doubt, buy the right to it or leave it.

Your donor is a discarded audio amplifier or receiver, the richest single haul in the waste stream: one case holds a mains transformer (the highest-value pull of all), a bank of large filter capacitors, power transistors and MOSFETs on heat sinks, a bridge rectifier, voltage regulators, and relays, and heavy linear amplifiers and receivers are still built this way—though many slim modern Class-D units use switch-mode supplies with far fewer big parts, so favor a weighty donor.43444547 It also carries the module's real hazard in textbook form: those filter capacitors hold a charge for days after the unit was last powered, and a vintage tube amplifier up to 700 volts, so this is where the discharge drill earns its place.46

What you open up: an amplifier's power supply is a mains transformer, a bridge rectifier, and a large filter capacitor. The transformer steps the voltage down, the bridge turns it to DC, and the capacitor smooths it.45 Drawn in KiCad.

Task: Salvage a discarded audio amplifier or receiver end to end: scout your area, source one legal donor, tear it down by the eight rules, read what it documents about itself, and test the parts you pull.
Condition: Given your own area and legal pulls only, the Unit 03 tool kit, the Module 02 multimeter, and a phone with an internet connection.
Standard: At least three venues surveyed and logged; one amplifier or receiver sourced from a legal channel and its exposure noted; the case opened by the eight rules and photographed before you disturb it, with the large filter capacitors bled through the resistor drill and read down on the meter to a couple of volts or less before your hands go near the board;46 one part named through the unit's own documentation, by an FCC-ID lookup or a service manual; the high-value pulls tested by Unit 06's methods and labeled with donor and test: the transformer (each winding low but not zero, primary to secondary open), the filter capacitors (discharged, then read), the power transistors or MOSFETs (diode test), the bridge rectifier (its four diodes), and any relays (coil resistance, contacts on continuity), with the heat sinks kept; the keepers boxed, the dead set aside, and the whole run logged with photographs.

Download the field exercise worksheet (PDF)

Task: Complete the Module 04 test.
Condition: Given twelve questions covering units one through six and the legal line, without reference to the module units or notes.
Standard: Answer at least ten of twelve questions correctly. For each question missed, reread the unit named in the feedback and retake the test until the standard is met.

continuity

A meter test for an unbroken electrical path. A good switch shows continuity when closed and none when open.

curtilage

The area immediately around a home that the law treats as part of it. Trash left outside the curtilage, at the curb, has no Fourth Amendment protection from a police search.

desoldering

Removing solder to free a part from a board, one joint at a time. Its own bench skill, with a standalone trainer in the series LABS; you cut instead wherever the leads allow.

e-waste

Discarded electronics: curbside trash, thrift-store rejects, and recycler stock. It is the free, anonymous channel you source from first.

FCC ID

The identifier printed on a device that transmits radio, opening a public regulatory file of external and internal photographs, the manual, and test reports; the schematic and parts list are often withheld for good.

parts pairing

Fingerprinting a component with a serial number so a genuine replacement refuses to work until the maker's software authorizes it. It is why a new part can be worth less to you than a salvaged one.

planned obsolescence

Building a product with an uneconomically short useful life so the customer buys again. The standing incentive that makes new hardware harder to repair and reuse.

reference designator

The letter-and-number code printed beside a part on a board, such as R4 or U7, that maps the part to its symbol on a schematic: R resistor, C capacitor, Q transistor, U integrated circuit.

stepper motor

A motor that turns in fixed steps rather than spinning freely, identified by its four, five, or six wires. Printers and drives are full of them.

teardown

The systematic disassembly of a device to recover its working parts. Unit 04's eight rules govern every one.

1. Ed Sobey, Unscrewed: Salvage and Reuse Motors, Gears, Switches, and More from Your Old Electronics, Chicago Review Press, 2011 (Light Fighter Library, Reference/Electronics): the Rules of the Hunt quoted in Unit 03, the tools list, the device-by-device treasure map and the Unscrewed Value Index, hidden fasteners (including the hard drive's label-hidden screw) and the cut-a-new-notch trick, wire-cutting and labeling discipline, the capacitor-discharge method and the exclusion of televisions and monitors, the 9-volt and multimeter test methods, motor identification by wire count, case reuse, and the hard-drive voice-coil detail. The teardown trainer's part lists, value indexes, hazards, step-by-step walkthroughs, and photographs (device pages 17–211, including the computer fan, toy remote control, DVD player, and UPS chapters used for the power- and sensing-relevant salvage in Unit 02) are taken from this book.
2. Simon Monk, Hacking Electronics, 2nd ed., McGraw-Hill, 2017 (Light Fighter Library, Reference/Electronics): Chapter 11 (Mending and Breaking Electronics) supplies the capacitor-discharge standard quoted in Unit 04 (the 100-ohm resistor in pliers, the meter check to about 50 volts, the never-with-a-screwdriver warning, and the lethal-device list of CRT sets, switch-mode supplies, and camera flash guns), the be-selective scavenging list with the cut-don't-desolder rule and leads left long enough to use, the fuse and battery-under-load tests with their thresholds, the LED forward-voltage figures cited in Unit 06, and the salvaged-fan fume extractor. Photographs credited to Monk are from these chapters' figures.
3. B. Millinkovich, "Scavenge Kit and Protocol," Volume III, Light Fighter Manifesto (Light Fighter Library, LFM Publications): the gopher-bag concept and its stealth-and-mobility principle, the supply-search shopping list and how it identifies high-probability locations and what to leave for next time, the day-and-night reconnaissance rule, the site hazard categories (unsound structures, confined spaces), the escape-or-abort-plan rule, and the legal-disclaimer register this section models. The itemized load-out list is course-side and is not reproduced here.
4. Privacy Guides, Private Payments and Cryptocurrency, and Financial Services (Gift Card Marketplaces) (Light Fighter Library, Reference/PrivacyGuides): cash as the best private-payment option, leaving no ledger tying a purchase to you (verified 2026-07-08; annotation rescoped 2026-07-10 to the claims this module still makes: the private-payment detail moved with the power arc).
5. Guerrilla-Tech salvage working notes (SCAVENGING-GUIDE, APPLIANCE-SALVAGE, COMPONENT-REFERENCE), Light Fighter working library: the scavenge-first sourcing hierarchy, e-scooter packs carrying 30 to 42 cells with dead packs usually holding only one or two bad ones, OpenWRT-capable router thresholds (8 MB+ flash, 64 MB+ RAM), newer inkjet printers using DC motors with encoders in place of steppers, the washing machine's water-level pressure switch (a mechanical type closing contacts at a set pressure, an electronic type shifting an oscillator's frequency with the level), and the warning that a CRT's capacitor can hold its charge for years. Working notes cross-checked against the primary sources cited above wherever a specific figure is stated.
6. Piotr Wciślik, "The Rubber Waistband and the Resistor: Solidarity Radio and Media Fantasies of Emancipation under Late Socialism in Poland," Acta Poloniae Historica 115 (2017), 179–210: Solidarity's underground radio built from store-bought parts (an audio cassette recorder, dural antenna tubing, a shielded cable, one transistor) for no more than a few tens of thousands of złotys, against an official broadcast system that, by Romaszewski's on-air boast of July 1982, imported almost 90 percent of its equipment from abroad, and kept deliberately cheap and disposable because the police learned to triangulate and seize transmitters. Peer-reviewed; cites the Proces Radia "Solidarność" trial typescript (HU OSA 300-50-1, box 1481) and RFE/RL Polish situation reports, event details pp. 194–198 (accessed 2026-07-08).
7. California v. Greenwood, 486 U.S. 35 (1988), Cornell Legal Information Institute: the Fourth Amendment does not prohibit the warrantless search and seizure of garbage left for collection outside the curtilage, and states may impose more stringent constraints under their own law (verified 2026-07-07).
8. Texas Penal Code § 30.05 (criminal trespass) and California Public Resources Code § 41950: notice by an enclosure designed to exclude intruders, and set-out recyclables becoming the property of the authorized recycling agent. These are jurisdiction-specific examples of a state patchwork (verified 2026-07-07).
9. California Business & Professions Code § 21606 (junk dealer records), EPA, Used Household Batteries, and the Electronics Recycling Coordination Clearinghouse: scrap-dealer recordkeeping requirements, the EPA rule against putting lithium and button cells in the trash, and the roughly twenty states plus DC whose laws ban electronics from landfills per the clearinghouse's table (nineteen plus DC on the clearinghouse's own count, up to twenty-three plus DC on broader 2025–26 tallies) (verified 2026-07-12; count updated 2026-07-12 from a stale "fifteen").
10. Fluke, "How to test diodes": the diode-test mode, in which a good diode reads its forward voltage in one direction and OL in the other (verified 2026-07-07; annotation rescoped 2026-07-09, the LED color figures are Monk's, src-2).
11. Hackaday, "Deducing Stepper Motor Wiring": identifying a salvaged stepper's coils with a meter, where two wires on the same coil read a finite resistance and two wires on different coils read open, and finding the center taps of five- and six-wire unipolar motors by their lower readings, the pair values clustering around two levels with the coil ends reading higher. That the tap reads about half is this module's own gloss: the tap sits mid-winding (verified 2026-07-07; annotation rescoped 2026-07-09).
12. Goodwill, "How to shop the buy-the-pound outlets", Consumer Reports on Buy Nothing and Freecycle, and the ARRL Hamfests and Conventions Calendar: current salvage venues, the pay-by-the-pound outlet bins, the local give-and-ask networks, and amateur-radio flea markets (verified 2026-07-07).
13. Legal Information Institute (Wex), Cornell Law School, "Abandoned Property": abandoned personal property is property an owner "intentionally relinquishes all rights to its control," whether property is abandoned is "a question of fact," and "real property may not be abandoned" (verified 2026-07-08).
14. Pull-A-Part, "Frequently Asked Questions": the self-service pull-and-haul salvage-yard model, with a required entry waiver ("all customers are required to sign a waiver before entering the yard"), a small admission fee, a minimum age with a photo ID that "may be required," bring-your-own-tools, and payment in cash or major cards (verified 2026-07-08).
15. iFixit, Essential Electronics Toolkit, Pro Tech Toolkit, and iOpener: the current teardown tool standard, a precision bit driver with "standard Phillips, Torx and flathead bits along with special Pentalobe, Torx Security and Tri-Point bits," the spudger's "flat end…for prying and separating," opening picks "inserted into the edges of the device," precision tweezers, a suction handle for glass panels, and a heat pouch "designed to apply heat directly and evenly to case components joined with adhesive" (verified 2026-07-08).
16. Material Focus, "6m vapes and pods are thrown away every week" (UK, 27 March 2026): "6.3 million vapes and pods" thrown away per week, 1.18 billion over four years, "vapes are powered by lithium-ion batteries, which if binned can get crushed or damaged and spark dangerous fires," a reduction of about a quarter following the 1 June 2025 single-use ban, and "80% of the materials inside a vape can be recovered" (UK figures; verified 2026-07-10).
17. EPA, Mercury in Consumer Products: "Mercury is used in LCD screens and monitors," and fluorescent lamps of all types are mercury-containing (verified 2026-07-08).
18. NTC "103" thermistor reference (10 kΩ at 25°C) and Schneider Electric (APC), UPS battery service life (three to five years): salvageable appliance sensors, the refrigerator NTC thermistor, and the fact that a dead UPS is usually a failed sealed-lead-acid battery rather than failed electronics (verified 2026-07-08).
19. Hengye Motor, "How to Test a DC Motor: Step-by-Step Guide with a Multimeter": a small DC motor's resistance across the terminals reads roughly 0.5 to 10 ohms and changes as the shaft turns, because the commutator segments switch under the brushes; a reading that stays open (OL) at every shaft position indicates a broken armature winding (verified 2026-07-09).
20. Fluke, "How to measure resistance with a digital multimeter": open, unconnected leads read OL; shorted leads read 0 ohms; the contacts of a good switch or relay read a very low resistance when closed (verified 2026-07-09).
21. California DTSC, "Guidance for Managing LCD Devices and LCD Device UW Lamps Residuals": the light source in an LCD monitor is typically a cold-cathode fluorescent lamp (CCFL), a transparent tube filled with mercury vapor; CCFLs removed from LCD panels are managed as universal waste when recycled and as hazardous waste when disposed of (verified 2026-07-10).
22. Repair Café International Foundation, "About": "Repair Cafés are free meeting places and they're all about repairing things (together)," with tools and materials on hand, expert volunteers, and electrical appliances among the things brought in for repair (verified 2026-07-09).
23. University of Washington, UW Surplus Store: "The Public Store is open to the general public every Tuesday," selling computers, monitors, lab glass, microscopes, TVs, machinery, and furniture, an example of the university-surplus channel (verified 2026-07-09).
24. Jeremy I. Bulow, "An Economic Theory of Planned Obsolescence," Quarterly Journal of Economics 101(4) (1986), 729–749: "Monopolists are shown to generally desire uneconomically short useful lives for their goods," planned obsolescence being "the production of goods with uneconomically short useful lives so that customers will have to make repeat purchases." Peer-reviewed and canonical; the module presents Swan's earlier invariance result (durability is independent of market structure) as the honest counter-position this model answers (verified 2026-07-10).
25. iFixit, "How Parts Pairing Kills Independent Repair": serialization "fingerprints each component" and pairs it to one device, so a genuine battery, display, or camera moved without the maker's software authorization loses function (the battery reports it cannot be verified; a display can disable Face ID). The count of serialized iPhone parts rising from two (2015) to nine (2020) is the European Right to Repair campaign's tally, not an Apple figure. The module does not claim only Apple can ever transplant a paired part (verified 2026-07-10).
26. FTC, "FTC, States Sue Deere & Company" (15 January 2025, N.D. Ill. 3:25-cv-50017, joined by the Illinois and Minnesota Attorneys General) and "FTC, States Secure Settlement with Deere & Company" (8 July 2026, by which point Arizona, Michigan, and Wisconsin had joined, five states in all): Deere gave its fully functional Service ADVISOR diagnostic software only to authorized dealers; the 2026 settlement requires Deere for ten years to give farmers and independent shops the same repair software and tools as dealers. The 2025 filing is an allegation; the 2026 settlement is the resolution (verified 2026-07-11; January state count corrected 2026-07-11).
27. Electronic Frontier Foundation, "What HP Must Do to Make Amends for Its Self-Destructing Printers", and the 2019 class-action settlement: an HP firmware update, disguised as a security update, made printers reject third-party and refilled ink cartridges (reported as false "cartridge damaged" or "missing" errors); HP settled a resulting class action in 2019 (a $1.5 million fund plus injunctive terms). Cited as a firmware lock that renders a working salvaged cartridge unusable (verified 2026-07-11).
28. Directive (EU) 2024/1799 on the repair of goods (in force, obligations applying from 31 July 2026): Article 5 bars manufacturers from using contractual, hardware, or software techniques that impede repair "unless justified by legitimate and objective factors including the protection of intellectual property rights." Repair advocates read the intellectual-property carve-out as a loophole that undermines the requirement (verified 2026-07-10).
29. U.S. Copyright Office, ninth triennial DMCA §1201 rule (effective 28 October 2024): the exemption permits circumventing a software lock to diagnose, maintain, or repair a lawfully acquired consumer device, but the anti-trafficking provisions of §1201 remain, so making or distributing the circumvention tool stays unlawful even where the repair circumvention itself is allowed (verified 2026-07-10).
30. Robert R. Leonhard and Jerome M. Conley, "Logistics," in Undergrounds in Insurgent, Revolutionary, and Resistance Warfare (2nd ed.), U.S. Army Special Operations Command / Johns Hopkins APL (Light Fighter Library, Tactics/Irregular), ch. 5, pp. 77–87: irregular forces have relied on battlefield recovery "since ancient times" to obtain arms, vehicles, communications equipment, food, and medical supplies; Italian factory workers pilfered radios from their plants for the WWII underground (p. 81); the Polish Home Army concealed a workshop above a welding shop to mask machine noise (p. 83). Used as doctrinal and historical framing only; the source's weapons-procurement specifics stay with the in-person course (verified 2026-07-10).
31. iFixit, "Choosing the Right Screwdriver Bit" and iFixit, "Pentalobe Screwdrivers": from the first, let the screw choose the bit, and a Japanese JIS screw, whose cross has square rather than tapered corners, cams out and strips a Phillips driver, so a JIS and a Phillips are "not always interchangeable"; from the second, the tamper-resistant five-point Pentalobe head, distinct from the six-point Torx, in the P2 size on iPhones and the P5 and P6 sizes on MacBooks (verified 2026-07-11).
32. iFixit, "How to Use iFixit Adhesive Remover": apply the solvent evenly along the elevated edge and wait two to three minutes for it to "penetrate and soften the adhesive" before lifting the part; the companion stretch-release technique pulls a battery pull-tab slowly and evenly at a low angle (verified 2026-07-10).
33. 47 CFR § 2.926 (FCC Identifier) and the FCC Equipment Authorization Search, with the FCC's confidentiality procedures (KDB 726920): an FCC ID is a grantee code assigned by the Commission plus a product code assigned by the grantee; a certification filing always exposes the ID label and location, the test report, and the RF-exposure information, and exposes internal and external photographs and the user manual after a short-term confidentiality window of up to 180 days, but schematics, block diagrams, operational descriptions, and parts lists may be granted permanent (long-term) confidentiality. Only a device bearing an FCC ID string, not merely the FCC logo, has a lookupable file (verified 2026-07-10).
34. Digi-Key, "PCB Markings: Reference Designator Meanings", following IEEE 315 / ASME Y14.44: printed-circuit reference designators are one or two letters plus a number, a near-universal convention that maps a part on the board to its symbol on the schematic: R resistor, C capacitor, L inductor, D diode (including LEDs), Q transistor, U integrated circuit, T transformer, K relay, F fuse, J jack or connector, SW switch (verified 2026-07-10).
35. ECIA, EIA weekly date codes (following EIA-476-A, Source and Date Code Marking): the industry-standard method of marking a component with the source and with the year and week of its manufacture, in the EIA form of a two-digit year followed by a two-digit week (YYWW) (verified 2026-07-12).
36. SMD Codebook (Rückl / Fairchild lineage): surface-mount parts are too small for a full type number and carry a two- or three-character code; the same code is assigned to different parts in different package styles, so a code must be resolved against the package and a code table, not read on its own (verified 2026-07-10).
37. Jonathan Bartlett, Electronics for Beginners: A Practical Introduction to Schematics, Circuits, and Microcontrollers, Apress, 2020 (Light Fighter Library, Reference/Electronics), ch. 11: an integrated circuit's package marks pin 1 with a notch or indentation, with the remaining pins numbered counterclockwise; power pins are labeled VCC, VDD, or V+ and ground GND, VEE, VSS, or V−; and a datasheet, though it assumes familiarity with the device, reliably gives what each pin does, the power requirements, the outer limits of operation, and often an example circuit (quoted from the Library full text; verified 2026-07-10).
38. K. Kübbeler, AVR TransistorTester documentation (the "TC1"-family component tester): the tester measures a capacitor's equivalent series resistance at a low frequency with a near-rectangular signal, well below the 100 kHz sine a datasheet quotes, so its ESR value is its own; it flags its limits plainly (thyristors and triacs need more than its ~6 mA test current, and inductance accuracy is poor). Used with the standing caution that ESR does not certify capacitance, so a suspect capacitor's value is checked separately, and that fixed pass-or-fail ESR thresholds are unreliable (verified 2026-07-10).
39. iFixit, "How to Remove a Stripped Screw": the stripped-screw removal ladder, least destructive first. iFixit's own steps are the rubber band laid over the head to fill the stripped recess and add grip and, as the last resort, a rotary tool cutting a fresh slot for a flathead to back the screw out; the screw-extractor rung the module places between them (a reverse-cut bit that bites turning counterclockwise) is the standard tool for the job, not one of iFixit's steps (verified 2026-07-12).
40. Toshiba, "Differences between the absolute maximum ratings and the recommended operating conditions": the absolute maximum ratings are values that must not be exceeded even for a moment, or the device may suffer breakdown, damage, or deterioration; the recommended operating conditions are the narrower range within which the part is guaranteed to operate normally (verified 2026-07-12).
41. Starting Electronics, "The Only Transistor Test You Need": a bipolar transistor is modelled as two diodes with their anodes joined at the base; in diode-test mode the positive (red) lead on the base of a good NPN reads a forward drop of about 0.6 to 0.7 volts to each of the collector and emitter, and the leads reverse for a PNP (verified 2026-07-12).
42. NextPCB, "How to Test MOSFETs": a healthy MOSFET has an intrinsic body diode across its drain and source, so in diode-test mode it reads a forward drop of about 0.4 to 0.7 volts in one direction and OL in the reverse; a reading in both directions or a dead short means the part has failed (verified 2026-07-12).
43. Volthaus Electronics Laboratory, "Electronic Components Salvage: Dumpster and Thrift Store Treasure": discarded audio power gear (a powered subwoofer or amplifier) is one of the richest thrift-store and curbside hauls, roughly a hundred dollars of working parts in a unit, led by its toroidal transformer at $25 to $50 or more; it also gives up good capacitors, power-amplifier ICs, and heat sinks, and the write-up notes an automotive ABS controller yields six high-current 12 V relays (verified 2026-07-12).
44. Clever Creations, "Salvaging Components from Old Electronics": an audio amplifier or sound system yields large smoothing capacitors, power MOSFETs and transistors, voltage regulators, inductors, and a mains transformer that supplies both a positive and a negative rail (verified 2026-07-12).
45. Lenard Audio Institute, "Amplifiers: Power Supply": an amplifier's capacitor-input supply is a large mains transformer (toroidal or EI) feeding a bridge rectifier of four diodes (about a 0.65 V drop across each) into large electrolytic filter capacitors, sized around 2000 µF for each ampere the supply must deliver (verified 2026-07-12).
46. Mojotone, "Filter Cap Discharge Procedure": an amplifier's filter capacitors are bled through a resistor, never shorted directly across the terminals, and then read on a meter set to its highest DC range until they settle to a couple of volts or less; amplifiers can hold a lethal charge for days after last use, and a vintage tube amplifier up to 700 V DC (verified 2026-07-12).
47. StereoIndex, "Arcam AVR20: AV receiver equipped with a powerful toroidal transformer": a current AV receiver (7 × 90 W at 8 Ω) built around a toroidal transformer, confirming that new amplifiers still use the same power-supply parts a salvaged one gives up (verified 2026-07-12).