The Fault Finder Course
Unit 1: The Root Cause Analysis Method
0/11 coreRead the machine before you touch it.
- LessonRoot cause thinkingCore CurriculumThe frame the whole course trains: fix the machine, then name what let it fail.Demo
- ScenarioVacuum pick station won’t pickDiscrete ManufacturingYour first machine: work the evidence, fix it, then name what capped the vacuum.Locked
- LessonThe 5 WhysCore CurriculumThe walking tool from the opener, held properly: verified answers, no blame, stop at a removable condition.Locked
- LessonWorking the candidate listCore CurriculumThe other tool from the opener: a list of competing explanations, and readings chosen for what they rule out.Locked
- LessonThe diagnostic mindsetCore CurriculumThe four-step loop the rest of the course runs on: gauge, localize, reason, then act.Locked
- MiniOne change at a timeCore CurriculumWhy a repair lands alone. Every live sim from here judges what you changed, and two changes make it unreadable.Locked
- LessonAsk what changedCore CurriculumMost faults have a start date. Where to get the story, and what to do when the answer is that nothing changed.Locked
- LessonKnowing normalCore CurriculumWhere a baseline comes from: the nameplate, the band on the gauge face, the trend, the twin, and a healthy machine.Locked
- SimThe cartoner went down mid-runDiscrete ManufacturingLive: the same question at the cartoner. No meter required. The HMI banner is a claim, and the walk tests it.Locked
- MiniEscalation & shift handoffCore CurriculumThe loop gets its boundary: the stop triggers, and the handoff that keeps your readings working after you clock out.Locked
- SimGlue temp warning will not clearDiscrete ManufacturingLive: one warning, three machines. The trend page against one card LED, and what changed doing the work.Locked
Unit 2: Safety & the meter
0/8 coreLock it out, prove it dead, and know when the reading lies.
- LessonSafe troubleshooting: lock it out, prove it deadCore CurriculumThe decision that precedes every measurement in the rest of the course: diagnose live, or lock it out first.Locked
- MiniTest before touchCore CurriculumLive-dead-live, the proof that turns a dead reading into something you can put your hands on.Locked
- LessonUsing your meter: when the reading liesCore CurriculumThe instrument itself, including the readings it invents: phantom voltage, and parallel paths in a resistance check.Locked
- MiniWhere the black lead goesCore CurriculumThe half of every voltage reading nobody states: what the black lead is referenced to, and where else it belongs.Locked
- MiniCAT ratings and test leadsCore CurriculumThe meter is safety equipment. What the CAT number covers, and why the leads wear out before the meter does.Locked
- SimThe CTN-250 refuses to resetDiscrete ManufacturingLive: a silent reset refusal, sorted with the meter alone. The voltage walk says which level died.Locked
- ScenarioLocked out, but the meter reads 48 VCore CurriculumThe unit's proving ground: a verify-dead check that reads 48 V, sorted with the technique from every reading above it.Demo
- SimThe cartoner reads running and no good cartons come off the endDiscrete ManufacturingLive: RUNNING on the badge and nothing good off the end. Both fuse checks, and a 480 V read with lead discipline.Locked
Optional practice: Free-roam the cartoner: find the disconnect, the fuse blocks, and the overload dials before anything is broken.
Unit 3: Power & circuits
0/10 coreWhat a circuit is, what the numbers should be, and how power reaches anything.
- LessonA circuit is a pathCore CurriculumThe ground the meter unit was standing on: series, parallel, and why an open reads full supply voltage across the gap.Locked
- MiniWhat the numbers should beCore CurriculumThe short list of magnitudes industrial circuits actually produce, so an impossible reading announces itself.Locked
- LessonInside the cabinet: power and the permission chainCore CurriculumThe cabinet vocabulary: the permission chain from E-stop to MCR, relay terminals, card LEDs, and the meter modes.Locked
- LessonThe power pathCore CurriculumThe map nothing has handed you yet: disconnect, supply, rails, cards, starters, and what a fault footprint says.Locked
- SimThe work order says: check the panelDiscrete ManufacturingLive: the panel as a power tree. Which family died names the branch, and a disagreeing rail names the trunk.Locked
- MiniNO vs NC in three minutesCore CurriculumWhat "normally" means on a contact, and why every stop in the panel you just walked is wired normally closed.Locked
- MiniRelay coil vs contactsCore CurriculumOne device, two separate circuits. The voltage printed for the coil says nothing about what the contacts switch.Locked
- MiniContactor vs relay vs SSRCore CurriculumThree ways a small signal switches a big load, where each one sits in the cabinet, and how each one fails.Locked
- MiniFuse, breaker, overload: who protects whatCore CurriculumThree protective devices that all interrupt a circuit, and the different thing each one is reporting when it does.Locked
- SimIt quits before the first cartonDiscrete ManufacturingLive: two fuses that fail identically and one that fails silently. One reading at the rail feed decides it.Locked
Optional practice: Free-roam the cartoner: find the disconnect, the fuse blocks, and the rails before anything is broken.
Unit 4: Signals
0/8 coreWhat the sensor says, and everything between it and the card.
- LessonReading the machine: sensors and photo-eyesCore CurriculumWhat a three-wire sensor actually says at its pins, and the sensor failures worth knowing by name.Locked
- MiniNPN vs PNP in 3 minutesCore CurriculumSinking or sourcing, settled with one meter reading at the black wire.Demo
- MiniReading sensor wiring diagramsCore CurriculumThe label on the sensor body is its datasheet: supply range, output type, and the pinout a replacement must match.Locked
- LessonSignal chains: from fuse to cardCore CurriculumFuse, device, wiring, terminal, card. Three faults look identical at the PLC, and halving the chain separates them.Locked
- SimThe case erector stopped confirming cartonsDiscrete ManufacturingLive cabinet. Every hidden cause here is something this unit taught you to see.Locked
- MiniAnti-static devices and why you ground themCore CurriculumYou have just handled a card in a live cabinet. How to hold a board so the swap does not leave the next fault behind.Locked
- MiniThrough-beam vs diffuse vs retroreflective photo-eyesCore CurriculumPlaced here on purpose: the sim closing this unit ends where the meter cannot reach, at the lens and the target.Locked
- SimThe erect station is faulting againDiscrete ManufacturingLive sequel: the wiring lane checks out and the eye itself is lying. The last step of the diagnosis is not electrical.Locked
Optional practice: Free-roam the cartoner: meter the sensor chains you just read about.
Unit 5: The PLC
0/6 coreThe controller is an instrument: the HMI banner, the step, and the I/O lights.
- LessonRead the PLC: the HMI banner, the step, and the I/O lightsCore CurriculumThe controller as an instrument: the HMI banner names a step and a witness, and the card LEDs say which end is lying.Locked
- MiniSourcing vs sinking I/O modulesCore CurriculumThe NPN and PNP question one level up, at the card. Some modules can be either one, once you find the jumper.Locked
- ScenarioEvery start dies on the same faultDiscrete ManufacturingTwo-stage: the HMI banner names a step, the work order blames the PLC. The cabinet LEDs partition the truth.Locked
- SimThe discharge end keeps stopping the lineDiscrete ManufacturingLive: one discharge input, read both ways. What the bit means when it is ON decides what the fault looks like.Locked
- MiniForcing I/O: the override and what it costsCore CurriculumA dead input invites the override. This is what the override costs, and the short list of times it is legitimate.Locked
- SimIt will not start and it will not say whyDiscrete ManufacturingLive: three silent-to-loud refusals. The controller reports only what it sees, and one silence is itself the finding.Locked
Optional practice: Free-roam the cartoner: read the HMI banner and step, and watch the I/O card LEDs.
Unit 6: The safety circuit
0/11 coreE-stops, guards, curtains, and the relay that watches them all.
- LessonHow safety circuits work: the circuit that must prove it can stopCore CurriculumThe architecture the unit trains against: de-energize to trip, two channels, EDM, and the never-jumper rule.Locked
- MiniSafety relay: read the LEDs before you reach for a meterCore CurriculumRead the relay face before reaching for a meter: the LEDs separate an open interlock circuit from a dead relay.Locked
- SimDead in the waterDiscrete ManufacturingLive opener: one vague write-up, three failures. The safety string, the fuse, and the SSR, sorted with the meter.Locked
- MiniE-stop anatomy: what the red button actually doesCore CurriculumBehind the red head: direct-opening contacts, the mechanical latch, and a contact block that can work loose.Locked
- MiniGuard interlocks: the switch that knows the doorCore CurriculumTongue, coded, and locking switches, what door sag does to each, and why a spare actuator is the dangerous part.Locked
- ScenarioGuard faults every shiftCore CurriculumGated RCA work: the fix is easy and enforced first. The close names what kept tripping the guard, and why.Locked
- SimGuard stop won’t resetDiscrete ManufacturingLive: five refusals behind one work order. The series walk, the FLT latch, and the EDM loop sort them all.Locked
- LessonLight curtains: the guard made of light, and how to believe itCore CurriculumA guard made of light. Its outputs test themselves faster than a meter can see, so the LEDs outrank your reading.Locked
- MiniNuisance trip or hard fault: classify before you chaseCore CurriculumWhich kind of trip you have picks the suspect list, and on a safety circuit that list starts out in the field.Locked
- MiniNever jumper a safety circuitCore CurriculumWhere troubleshooting ends and lockout begins, and what a wire across a contact costs once it stays there.Locked
- SimThe line holds and the curtain shows nothingDiscrete ManufacturingLive: supply, assertion, glass, and the run into the relay, in that order. One pair falls to a walk down the aisle.Locked
Optional practice: Free-roam the cartoner: trip the e-stop, open the guard, block the curtain, and watch the safety relay LEDs.
Unit 7: Air, heat & timingDiscrete Manufacturing
0/8 coreFaults where every part “works.”
- LessonAir and vacuum: pressure, seals, and reed switchesFive stories cover almost every air fault: supply, restriction, actuator, seal, and the switch that reports on them.Locked
- MiniFlow vs pressure: slow is not weakPressure sets how hard the cylinder pushes and flow sets how fast. A slow stroke and a weak one differ in cause.Locked
- SimVacuum pick can't hold the blankLive: the gauge tells the truth only while the attempt is live. Re-start and read the vacuum mid-pick.Locked
- LessonProcess and timing: glue, resolvers, and cam windowsThe other half of this unit: a temperature wrong for the job, and the right action firing at the wrong angle.Locked
- MiniRTDs vs thermocouples: how each one failsThe glue pot temperature came from one of these two devices, and each one lies in its own characteristic way.Locked
- SimEvery part "works": the flaps still popLive: nothing faults and every part reads healthy. The pot temperature, the temp light, and one popped flap decide.Locked
- MiniEncoders and resolvers: position as a signalPosition as a signal, carried on an output that no ordinary input card can read.Locked
- SimNothing has run right since the weekend PMLive closer: the PM touched one window, the whole clock, or a part. Where the glue lands decides which.Locked
Optional practice: Free-roam the cartoner: watch vacuum, glue temperature, and timing interact.
Unit 8: Hard cases
0/8 coreAmbiguous readings, faults that hide, prints that lie.
- LessonAmbiguity: when one reading fits several causesCore CurriculumWhat a reading buys you: it shrinks the candidate list, and the next probe is chosen for how much it shrinks it.Locked
- ScenarioWeak vacuum, but why?Discrete ManufacturingThe Unit 1 station, guardrails removed. This time the diagnosis is yours to commit.Locked
- LessonIntermittent faultsCore CurriculumWhen the fault will not appear on demand, stop chasing it. Protect the evidence, log the occurrences, and set a trap.Locked
- MiniGround loops: when two grounds are worse than oneCore CurriculumOne reason an analog signal reads noisy while every part is healthy: the machine is bonded to earth in two places.Locked
- LessonCognitive traps in troubleshootingCore CurriculumThe four ways the searcher rigs the search: the anchor, the friendly probe, the last-time story, the parts cannon.Locked
- SimIt ran fine on product ADiscrete ManufacturingLive: the write-up blames a swapped eye. The meter decides whether the history is the story.Locked
- LessonDocumentation vs. realityCore CurriculumPlaced between the unit’s two sims: both hand you a prior conclusion in writing, and this is what it is worth.Locked
- SimIt is still not making cartonsDiscrete ManufacturingLive: a crew has already cleared the vacuum side. Weigh that against a fuse, a stack of board, and crushed board.Locked
Unit 9: Rotating equipment
0/7 coreBearings, belts, chains, couplings: read the wear, then find what made it.
- LessonBearings and lubricationCore CurriculumThe film is the part that runs. Five wear signatures on the bench, three free instruments at the machine.Locked
- ScenarioThe bearing that keeps failingCore CurriculumAutopsy first: the bench says how it died, the live machine says the condition is back, the records say why.Locked
- MiniVibration as evidenceCore CurriculumThe free reading: a hand on the housing and a screwdriver to the ear, and when to call for real instruments.Locked
- MiniBelts and chainsCore CurriculumThe part you replace runs on a mate that wore with it. Tension, elongation, and tooth profile have numbers.Locked
- ScenarioThe chain that keeps jumpingCore CurriculumEvery replacement runs quiet at first. The bench measurement and the records say why the quiet never lasts.Locked
- MiniCouplings and gearboxesCore CurriculumThe vocabulary the course capstone assumes: the spider is a sacrificial witness, and how it dies names the killer.Locked
- SimThe line has slowed down and nothing has faultedDiscrete ManufacturingLive: a slow machine will not fault. The last stroke against the last whole index says where the time went.Locked
Unit 10: Motors & drives
0/9 coreWindings, rotation, the drive that commands them, and what really trips the overload.
- MiniMotor rotation direction: what wiring can and cannot reverseCore CurriculumWhat wiring can and cannot reverse. Some motors flip at the terminals, others have it built into the copper.Locked
- ScenarioThe overload keeps trippingCore CurriculumTwo-stage: commit a domain before you commit a cause. The overload named the motor; the cause need not live there.Locked
- LessonRead the VFD keypad before you reach for a meterCore CurriculumThe drive commanding the motor is also watching it: Hz, amps, and the code line, wired in before the fault.Locked
- MiniVFD trip codesCore CurriculumThe keypad code line, decoded: what each of the five trips accuses, and the first thing to check for each.Locked
- MiniWye vs delta: motor winding configurationsCore CurriculumWye or delta decides what voltage each coil sees, and the strapping in the terminal box is what amps read against.Locked
- MiniHow a servo system worksDiscrete ManufacturingController, drive, motor, and encoder in one loop, and the following error that loop exists to close.Locked
- SimThe shaft turns and no cartons come outDiscrete ManufacturingLive: motion is the drive job and position is the sensor job. Watch the shaft, then read the prox against it.Locked
- MiniCommon motion control faults and their causesDiscrete ManufacturingThe named failures behind the motion you just watched: following error, tuning, and the feedback in the loop.Locked
- SimThe badge says RUNNING and nothing is movingDiscrete ManufacturingLive: three failures in the torque path behind one quiet badge. Walk the volts, then weigh a walk that found nothing.Locked
Unit 11: Triage
0/4 coreThe symptom lies about its domain. Call the right trade first.
- LessonTriage: when the symptom lies about its domainCore CurriculumPresenting domain against home domain. An overload trip reads electrical and can be a dragging bearing.Locked
- SimThe tucker keeps stallingDiscrete ManufacturingLive two-stage: the HMI banner names the step that timed out. The carton in the tucker pocket is the only witness.Locked
- ScenarioThe press cycles slowDiscrete ManufacturingThe manufacturing capstone: a real machine to solve.Locked
- SimThe CTN-250 will not startDiscrete ManufacturingLive two-stage: three systems can refuse a start. Verify each claim with one reading, then route the callout.Locked
Unit 12: Past the fix
0/5 coreThe machine runs again. Name the condition that killed the part and prove it is gone.
- LessonProving the fixCore CurriculumWhat a clean run is, decided before you start one: real load, enough time, and a check on what the repair disturbed.Locked
- ScenarioThe coupling that keeps shearingCore CurriculumFit the part, run it clean, then earn the close by naming what keeps killing it.Locked
- SimThe erect eye fault came backDiscrete ManufacturingLive: a repaired station faults on the same HMI banner. The repair history is evidence. Attribute the recurrence.Locked
- MiniDocumenting the fixCore CurriculumThe close you just earned, written so the next "what changed?" has an answer. The last two sims spend it.Locked
- SimIt keeps running out of blanksDiscrete ManufacturingLive: the magazine keeps running dry and reloading keeps not settling it. Three fixes, and one is aimed right.Locked