The Fault Finder Course

Unit 1: The Root Cause Analysis Method

0/10 core

Read the machine before you touch it.

  1. LessonRoot cause thinkingCore Curriculum · 5 minThe frame the whole course trains: fix the machine, then name what let it fail.Demo
  2. LessonThe 5 WhysCore Curriculum · 5 minThe walking tool from the opener, held properly: verified answers, no blame, stop at a removable condition.Locked
  3. LessonWorking the candidate listCore Curriculum · 6 minThe other tool from the opener: a list of competing explanations, and readings chosen for what they rule out.Locked
  4. LessonThe diagnostic mindsetCore Curriculum · 5 minThe four-step loop the rest of the course runs on: gauge, localize, reason, then act.Locked
  5. MiniOne change at a timeCore Curriculum · 3 minWhy a repair lands alone. Every live sim from here judges what you changed, and two changes make it unreadable.Locked
  6. LessonAsk what changedCore Curriculum · 5 minMost faults have a start date. Where to get the story, and what to do when the answer is that nothing changed.Locked
  7. LessonKnowing normalCore Curriculum · 6 minWhere a baseline comes from: the nameplate, the band on the gauge face, the trend, the twin, and a healthy machine.Locked
  8. SimIt ran fine yesterday, so what changed?Process Industry · 10 minLive: the lesson’s question, asked at a running machine. No meter, just looking, reading, and Syd.Locked
  9. MiniEscalation & shift handoffCore Curriculum · 4 minThe loop gets its boundary: the stop triggers, and the handoff that keeps your readings working after you clock out.Locked
  10. SimTS-3 will not get through a startProcess Industry · 10 minLive: four start deaths behind one write-up. The step field forgets, the event log remembers. Rebuild the timeline.Locked

Unit 2: Safety & the meter

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Lock it out, prove it dead, and know when the reading lies.

  1. LessonSafe troubleshooting: lock it out, prove it deadCore Curriculum · 8 minThe decision that precedes every measurement in the rest of the course: diagnose live, or lock it out first.Locked
  2. MiniTest before touchCore Curriculum · 4 minLive-dead-live, the proof that turns a dead reading into something you can put your hands on.Locked
  3. LessonUsing your meter: when the reading liesCore Curriculum · 9 minThe instrument itself, including the readings it invents: phantom voltage, and parallel paths in a resistance check.Locked
  4. MiniWhere the black lead goesCore Curriculum · 4 minThe half of every voltage reading nobody states: what the black lead is referenced to, and where else it belongs.Locked
  5. MiniCAT ratings and test leadsCore Curriculum · 3 minThe meter is safety equipment. What the CAT number covers, and why the leads wear out before the meter does.Locked
  6. ScenarioLocked out, but the meter reads 48 VCore Curriculum · 8 minThe unit's proving ground: a verify-dead check that reads 48 V, sorted with the technique from every reading above it.Demo
  7. SimStart refused with the panel LEDs darkProcess Industry · 10 minLive: one refusal message, three worlds. The meter proves the rail and the device, then hits its limit at the bay.Locked

Optional practice: Free-roam the TS-3 skid: find the disconnect, the fuse blocks, and the overload dials before anything is broken.

Unit 3: Power & circuits

0/8 core

What a circuit is, what the numbers should be, and how power reaches anything.

  1. LessonA circuit is a pathCore Curriculum · 8 minThe ground the meter unit was standing on: series, parallel, and why an open reads full supply voltage across the gap.Locked
  2. MiniWhat the numbers should beCore Curriculum · 5 minThe short list of magnitudes industrial circuits actually produce, so an impossible reading announces itself.Locked
  3. LessonInside the cabinet: power and the permission chainCore Curriculum · 8 minThe cabinet vocabulary: the permission chain from E-stop to MCR, relay terminals, card LEDs, and the meter modes.Locked
  4. LessonThe power pathCore Curriculum · 8 minThe map nothing has handed you yet: disconnect, supply, rails, cards, starters, and what a fault footprint says.Locked
  5. MiniNO vs NC in three minutesCore Curriculum · 3 minWhat "normally" means on a contact, and why every stop in the panel you just walked is wired normally closed.Locked
  6. MiniRelay coil vs contactsCore Curriculum · 5 minOne device, two separate circuits. The voltage printed for the coil says nothing about what the contacts switch.Locked
  7. MiniContactor vs relay vs SSRCore Curriculum · 5 minThree ways a small signal switches a big load, where each one sits in the cabinet, and how each one fails.Locked
  8. MiniFuse, breaker, overload: who protects whatCore Curriculum · 5 minThree protective devices that all interrupt a circuit, and the different thing each one is reporting when it does.Locked

Optional practice: Free-roam the TS-3 skid: find the disconnect, the fuse blocks, and the rails before anything is broken.

Unit 4: Signals

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What the sensor says, and everything between it and the card.

  1. LessonReading the machine: sensors and photo-eyesCore Curriculum · 7 minWhat a three-wire sensor actually says at its pins, and the sensor failures worth knowing by name.Locked
  2. MiniNPN vs PNP in 3 minutesCore Curriculum · 3 minSinking or sourcing, settled with one meter reading at the black wire.Demo
  3. MiniReading sensor wiring diagramsCore Curriculum · 5 minThe label on the sensor body is its datasheet: supply range, output type, and the pinout a replacement must match.Locked
  4. LessonSignal chains: from fuse to cardCore Curriculum · 7 minFuse, device, wiring, terminal, card. Three faults look identical at the PLC, and halving the chain separates them.Locked
  5. MiniAnti-static devices and why you ground themCore Curriculum · 5 minYou 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
  6. MiniReading 4–20 mA loopsProcess Industry · 5 minThe live zero: 4 mA is the bottom of scale, so 0 mA is a broken loop, and the shunt read tells those two apart.Locked
  7. SimThe suction reading diedProcess Industry · 10 minThe lessons’ fuse → device → wire hunt, told in milliamps on a live current loop.Locked
  8. SimFlow reading will not reach setpointProcess Industry · 9 minLive: a loop that is alive, legal, and scaled wrong. The work being paid for, held against the number reported.Locked
  9. MiniThrough-beam vs diffuse vs retroreflective photo-eyesCore Curriculum · 5 minPlaced here on purpose: the sim closing this unit ends where the meter cannot reach, at the lens and the target.Locked
  10. SimThe seal temperature reading looks wrongProcess Industry · 11 minLive: a reading the operator does not trust, settled at the card. One shunt-volts measurement sorts all three.Locked

Optional practice: Free-roam the TS-3 skid: meter the transmitters and their signal chains.

Unit 5: The PLC

0/5 core

The controller is an instrument: the HMI banner, the step, and the I/O lights.

  1. LessonRead the PLC: the HMI banner, the step, and the I/O lightsCore Curriculum · 9 minThe controller as an instrument: the HMI banner names a step and a witness, and the card LEDs say which end is lying.Locked
  2. MiniSourcing vs sinking I/O modulesCore Curriculum · 5 minThe NPN and PNP question one level up, at the card. Some modules can be either one, once you find the jumper.Locked
  3. SimTS-3 trips seconds after every startProcess Industry · 11 minLive: the same bit-direction question on the skid. A valve prox, the air gauge, and X1:6 say whether to trust it.Locked
  4. MiniForcing I/O: the override and what it costsCore Curriculum · 4 minA dead input invites the override. This is what the override costs, and the short list of times it is legitimate.Locked
  5. SimThe rate is falling and no alarm comes upProcess Industry · 11 minLive: the warning line is the PLC repeating a switch. A falling rate, a silent HMI screen, and the meter at the dial.Locked

Optional practice: Free-roam the TS-3 skid: read the HMI and the I/O card LEDs against what the machine is doing.

Unit 6: The safety circuit

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E-stops, guards, curtains, and the relay that watches them all.

  1. LessonHow safety circuits work: the circuit that must prove it can stopCore Curriculum · 10 minThe architecture the unit trains against: de-energize to trip, two channels, EDM, and the never-jumper rule.Locked
  2. MiniSafety relay: read the LEDs before you reach for a meterCore Curriculum · 5 minRead the relay face before reaching for a meter: the LEDs separate an open interlock circuit from a dead relay.Locked
  3. SimTS-3 does not answer the buttonsProcess Industry · 10 minLive: three kinds of silence behind one dead-machine write-up. Two readings prove the rail and the string first.Locked
  4. MiniE-stop anatomy: what the red button actually doesCore Curriculum · 4 minBehind the red head: direct-opening contacts, the mechanical latch, and a contact block that can work loose.Locked
  5. MiniGuard interlocks: the switch that knows the doorCore Curriculum · 5 minTongue, coded, and locking switches, what door sag does to each, and why a spare actuator is the dangerous part.Locked
  6. ScenarioGuard faults every shiftCore Curriculum · 12 minGated RCA work: the fix is easy and enforced first. The close names what kept tripping the guard, and why.Locked
  7. LessonLight curtains: the guard made of light, and how to believe itCore Curriculum · 9 minA guard made of light. Its outputs test themselves faster than a meter can see, so the LEDs outrank your reading.Locked
  8. MiniNuisance trip or hard fault: classify before you chaseCore Curriculum · 4 minWhich kind of trip you have picks the suspect list, and on a safety circuit that list starts out in the field.Locked
  9. MiniNever jumper a safety circuitCore Curriculum · 5 minWhere troubleshooting ends and lockout begins, and what a wire across a contact costs once it stays there.Locked
  10. SimTS-3 will not take a resetProcess Industry · 8 minLive: the unit’s one callout where the relay is guilty. Rail, channel, output, and two of three clear the string.Locked

Optional practice: Free-roam the TS-3 skid: find fuse F1 and the safety relay K1S, and probe the string end to end.

Unit 7: Hard cases

0/7 core

Ambiguous readings, faults that hide, prints that lie.

  1. LessonAmbiguity: when one reading fits several causesCore Curriculum · 6 minWhat a reading buys you: it shrinks the candidate list, and the next probe is chosen for how much it shrinks it.Locked
  2. LessonIntermittent faultsCore Curriculum · 6 minWhen the fault will not appear on demand, stop chasing it. Protect the evidence, log the occurrences, and set a trap.Locked
  3. MiniGround loops: when two grounds are worse than oneCore Curriculum · 5 minOne reason an analog signal reads noisy while every part is healthy: the machine is bonded to earth in two places.Locked
  4. LessonCognitive traps in troubleshootingCore Curriculum · 6 minThe four ways the searcher rigs the search: the anchor, the friendly probe, the last-time story, the parts cannon.Locked
  5. SimTS-3 runs, but nothing movesProcess Industry · 10 minLive: two trips telling the truth about different mechanics, and one instrument lying while nothing trips at all.Locked
  6. LessonDocumentation vs. realityCore Curriculum · 5 minPlaced between the unit’s two sims: both hand you a prior conclusion in writing, and this is what it is worth.Locked
  7. SimTS-3 keeps tripping on dry runProcess Industry · 10 minLive: one dry-run banner over three machines, one a deadhead. The HMI screen against the local gauge breaks the tie.Locked

Unit 8: Rotating equipment

0/8 core

Bearings, belts, chains, couplings: read the wear, then find what made it.

  1. LessonBearings and lubricationCore Curriculum · 11 minThe film is the part that runs. Five wear signatures on the bench, three free instruments at the machine.Locked
  2. ScenarioThe bearing that keeps failingCore Curriculum · 12 minAutopsy first: the bench says how it died, the live machine says the condition is back, the records say why.Locked
  3. MiniVibration as evidenceCore Curriculum · 4 minThe free reading: a hand on the housing and a screwdriver to the ear, and when to call for real instruments.Locked
  4. SimStill short of rate after the impeller was changedProcess Industry · 12 minLive: the impeller was changed and the rate is still short. The ear, the sight glass, and amps against Hz decide.Locked
  5. MiniBelts and chainsCore Curriculum · 5 minThe part you replace runs on a mate that wore with it. Tension, elongation, and tooth profile have numbers.Locked
  6. ScenarioThe chain that keeps jumpingCore Curriculum · 10 minEvery replacement runs quiet at first. The bench measurement and the records say why the quiet never lasts.Locked
  7. MiniCouplings and gearboxesCore Curriculum · 5 minThe vocabulary the course capstone assumes: the spider is a sacrificial witness, and how it dies names the killer.Locked
  8. SimThe amps on P-101 keep climbingProcess Industry · 11 minLive: the logged amps have climbed all week. Where the extra work goes is the question, and only the keypad answers.Locked

Unit 9: Motors & drives

0/9 core

Windings, rotation, the drive that commands them, and what really trips the overload.

  1. MiniMotor rotation direction: what wiring can and cannot reverseCore Curriculum · 5 minWhat wiring can and cannot reverse. Some motors flip at the terminals, others have it built into the copper.Locked
  2. ScenarioThe overload keeps trippingCore Curriculum · 10 minTwo-stage: commit a domain before you commit a cause. The overload named the motor; the cause need not live there.Locked
  3. LessonRead the VFD keypad before you reach for a meterCore Curriculum · 10 minThe drive commanding the motor is also watching it: Hz, amps, and the code line, wired in before the fault.Locked
  4. MiniVFD trip codesCore Curriculum · 3 minThe keypad code line, decoded: what each of the five trips accuses, and the first thing to check for each.Locked
  5. SimTS-3 transfer won’t make rateProcess Industry · 10 minLive: the VFD keypad is free instrumentation. Hz, amps, and the fault code sort three trips that look alike.Locked
  6. MiniWye vs delta: motor winding configurationsCore Curriculum · 5 minWye or delta decides what voltage each coil sees, and the strapping in the terminal box is what amps read against.Locked
  7. SimP-101 keeps tripping: read the code line before you resetProcess Industry · 10 minLive: three trips that read the same on the work order. The code line says who tripped, the HMI banner says why.Locked
  8. SimP-101 amps do not match the jobProcess Industry · 9 minLive: motor current is a work meter. More amps than the job, fewer, and none at all are three different machines.Locked
  9. SimTS-3 tripped on motor temp againProcess Industry · 10 minLive: two machines carry the same HIGH MOTOR TEMP banner on the HMI, and the thermostat contact says which earned it.Locked

Optional practice: Free-roam the TS-3 skid: read the drive keypad against what the motor is doing on a machine that is running well.

Unit 10: Triage

0/3 core

The symptom lies about its domain. Call the right trade first.

  1. LessonTriage: when the symptom lies about its domainCore Curriculum · 6 minPresenting domain against home domain. An overload trip reads electrical and can be a dragging bearing.Locked
  2. SimTS-3 seal leak alarmProcess Industry · 12 minLive two-stage: the tray alarm names the witness. Commit whose problem it is before you touch the seal.Locked
  3. SimTS-3 refuses every startProcess Industry · 12 minLive two-stage: the same refusal on the skid. The keypad, the bay, and one gauge say which system signed the claim.Locked

Unit 11: The pump roomProcess Industry

0/11 core

The skid in depth: the sanitary side, pump curves, and seals that keep failing.

  1. LessonThe sanitary side of troubleshooting · 7 minCIP, tri-clamp, EPDM, and the PMO change what a fault looks like.Locked
  2. LessonPumps: curves, cavitation, and the amps that lie · 8 minHead against flow: which is short says where to look. A deadheaded pump draws less current, which catches people out.Locked
  3. MiniNPSH in five minutes · 5 minAvailable minus required is the margin. When it runs out, the liquid boils at the impeller.Locked
  4. MiniStrainer ΔP as evidence · 4 minThe pressure drop across the basket separates a blinded screen from a throttled valve faking the same starved suction.Locked
  5. ScenarioThe transfer can't keep up · 12 minBracket the pump with its two gauges: fouled strainer, throttled inlet, worn impeller, or a speed reference left low.Locked
  6. SimP-101 transfer starves mid-shift · 15 minLive capstone on the running skid: four quiet underperformers dealt at random. The trend is the tell.Locked
  7. LessonMechanical seals: reading the autopsy · 7 minThe faces and the elastomer are the witness, and each failure signature points at a condition outside the seal.Locked
  8. ScenarioThird seal in five weeks · 10 minThe failed part is the witness, and the root cause always lives outside the seal.Locked
  9. MiniWhen valve feedback lies · 4 minThe prox usually watches the actuator, and the disc can part company with it while the HMI still reports open.Locked
  10. ScenarioChangeover, and now it pumps nothing · 12 minTwo-stage capstone: it presents process, lives mechanical, and the HMI is lying about the valve.Locked
  11. SimLow flow on P-101, second call this week · 12 minLive coda: the gauge against the HMI screen. A number that goes flat while the needle walks is the finding.Locked

Optional practice: Free-roam the TS-3 skid: inject faults yourself in the sandbox.

Unit 12: Past the fix

0/5 core

The machine runs again. Name the condition that killed the part and prove it is gone.

  1. LessonProving the fixCore Curriculum · 6 minWhat a clean run is, decided before you start one: real load, enough time, and a check on what the repair disturbed.Locked
  2. ScenarioThe coupling that keeps shearingCore Curriculum · 12 minFit the part, run it clean, then earn the close by naming what keeps killing it.Locked
  3. SimThe new seal is leaking tooProcess Industry · 10 minLive: the seal was replaced and the leak callout is back. The temperature history says which fix would hold.Locked
  4. MiniDocumenting the fixCore Curriculum · 4 minThe close you just earned, written so the next "what changed?" has an answer. The last two sims spend it.Locked
  5. SimTS-3 has not run right since the washProcess Industry · 10 minLive: the same complaint returns after every CIP wash and the fix never sticks. The recurrence is the evidence.Locked