The method behind this example
Repair only what the evidence supports, then test the original symptom again.
Your independent challenge: This example has two simultaneous faults; the assigned model has one. Use its observed trace, not this cable-and-lamp answer.
The example includes the practical intervention and its required handover.
Start this worked example
- Choose Watch the worked example. The student demonstrator explains the task, talks through each action, then reviews the observations and finished submission. Narration starts with this click; Mute narration keeps the same experience captioned.
- Choose Take control to try the current chapter. Follow its prompt, change the labelled controls and select Test my decision.
- Read the feedback, retry if needed, then continue with Next chapter. Each checked chapter provides evidence for one connected operation.
- After every chapter check, return to the mission station, perform the intervention, collect its package and follow the marked checkpoints to complete the handover. Watching performs these same actions with narration. Direct chapter access is a partial preview until the full evidence and handover are complete.
- Use Fullscreen mission after opening the scene to keep the instructions, chapter controls and equipment together. Reflections and exports come after your practical attempt.
This is an alternate example, not your assigned exercise. Your course task is linked after the player.
YOUR SKILL
Electronic fault diagnosis
A NEW SETTING
One fictional nine-volt beacon whose fault card permits more than one open component at the same time.
WHAT CHANGES
The assigned browser and campus circuits each contain exactly one open fault. This single beacon contains a cable break and an open lamp together: the first correct repair restores supply but does not restore light.
Scene guide · people, evidence and object placement
People and the beacon with several possible faults
One nine-volt bench beacon remains under investigation throughout; its case rule permits simultaneous faults.
- Your part
- Watch follows a worked solution. Take control lets you move the student avatar and try its decisions. The demonstrator in the explanation is modelling a solution, not an extra witness in the story.
- Your instructor
- Mara stands in the marked teaching bay outside the investigation area. She guides the exercise. Her presence, appearance and idle gestures are not clues about what happened in the case.
- People in this scenario
- The example learner performs the recorded tests and repairs. Mara is the teaching guide; her gestures and the room lights are not measurements.
- What counts as evidence
- Use named probe readings, isolated continuity and the same beacon’s light output. Preserve any failed verification after a repair; a repaired prerequisite does not prove the whole device works.
- Why the objects are here
- The beacon is one labelled circuit rig. It is not exchanged for a second specimen between chapters. Its multiple-fault rule differs from the assigned lab’s one-fault configurations.
Systems Garage
Watch the complete alternate example. Take control of the equipment whenever you are ready.
An alternate example · separate from your assessed workHow to move, inspect and complete the activity
Use WASD or arrow keys to walk. Press E near an instrument to examine it. Inspect means read its details; Use equipment performs the action named in its status message. The task controls let you choose exact settings and test a solution. Once verified, use the mission station to put it into effect, collect the resulting evidence or cargo, follow its checkpoints and complete the handover at the receiving station.
Scroll over the scene or use Zoom + / Zoom − for a closer or wider view. Click and drag to turn whenever the cursor is free. Choose Fullscreen mission to keep the scene, mission instructions and all task controls together. Fullscreen starts with a free cursor so you can scroll the panel and choose options. Press X or Lock cursor (X) to turn by moving the mouse. Press X again to free the cursor and return to click-and-drag turning. Tab also frees the cursor. The X shortcut stays inactive while typing or choosing a form value. Press Escape or Exit fullscreen to return to the page. On touchscreens, drag to look and use the zoom buttons. If your browser cannot enter native fullscreen, the mission expands to fill its window.
Choose Watch to follow the worked example, or Take control to try it yourself. The transcript and completed example remain available if 3D is unavailable. Demonstrations never change assessed progress.
I must restore one fictional nine-volt beacon. This case allows more than one fault at the same time, unlike the assigned lab's single-fault cases. I will locate a supported supply fault, make a controlled repair, test the original symptom, and continue if the beacon still fails. My diagnosis must preserve the incomplete first repair as well as the final working result. The method we are practising is: Repair only what the evidence supports, then test the original symptom again.. Our field objective is: Restore the conservatory beacon and hand its two-fault diagnosis to the service team. Repairing the open cable restores supply but leaves the same beacon dark. I will perform the supported intervention and handover. You can pause, mute, replay, or take control at any point. The captions show the same explanation.
Narration starts after you choose Watch or Play. Captions remain available if this browser has no working voice.
Perform the practical outcome
Each chapter provides evidence for this operation. Inspect, investigate, act, and complete the handover.
FIELD OPERATION · Briefing
Operation Twin Fault
Restore the conservatory beacon and hand its two-fault diagnosis to the service team.
Repairing the open cable restores supply but leaves the same beacon dark.
Inspect the mission station to begin your investigation.
Nothing collected.
Mission actions become available when the activity loads.
Mission record and accessible controls
These controls perform the same actions as the marked stations in the scene. Use them with a keyboard or touch, or when graphics are unavailable. Equipment tests establish whether your intervention is supported. The final handover records a mission outcome; your explanation is assessed separately.
- No mission actions yet.
The complete transcript and finished example are available below while the player loads.
THE DEMONSTRATOR’S REASONING
Read the case rule and initial trace
The case card says this one beacon may contain several faults at once. With power on, source and fuse outputs read 9 V; cable output and beacon supply read 0 V. The dark lamp cannot yet tell us whether its own load is healthy because supply is missing.
Why this matters
A known supply break can hide a second defect. The assigned single-fault assumption does not apply to this example.
A plausible mistake
Importing the assigned lab’s one-fault guarantee would make the first diagnosis falsely exhaustive.
WHAT THE DEMONSTRATOR DID
YOUR LEARNING CONTROLS
Make the skill your own.
Record the powered source and the case rule before diagnosing.
Watch the apparatus change as the student demonstrates. Take control whenever you want to test the same idea yourself.
BASED ON YOUR ATTEMPTS
Watching and practising are recorded separately in this visit. These examples do not change your assessed work or skills passport.
NOW TRANSFER THE SKILL
Carry the method into your own work.
This example has two simultaneous faults; the assigned model has one. Use its observed trace, not this cable-and-lamp answer.
A COMPLETE WORKED SUBMISSION
Completed example — beacon with two faults
Example work from this demonstration's scenario. Use it to understand the expected evidence and explanation, then make your own decisions in the assigned activity.
Download the complete exampleRead the finished work
Completed demonstration example — beacon with two faults
This is one fictional nine-volt beacon throughout the attempt. Its published case card allows multiple simultaneous open faults. The assigned browser and campus lab instead introduce exactly one fault at a time.
Initial evidence and first diagnosis
With power on, source / fuse output / cable output / lamp supply read 9 / 9 / 0 / 0 V relative to the common return. The lamp was dark. The first missing supply supported an open cable. The unpowered lamp's own condition remained unresolved; the readings did not prove it healthy.
First repair and failed whole-system check
I isolated the source and replaced the cable only. After restoring power, the trace became 9 / 9 / 9 / 9 V, but the same beacon stayed dark. The repair successfully restored supply without resolving the original symptom. I preserved both statements instead of calling the cable diagnosis wrong or declaring the job complete.
Second diagnosis and repair
With healthy supply and a dark load, I isolated power and tested lamp continuity. The result was open. I replaced that confirmed open lamp while isolated, then restored power. The supply remained 9 / 9 / 9 / 9 V and the lamp lit.
Preserved diagnostic chain
| Stage | Supported finding | Action | Verification |
|---|---|---|---|
| Initial trace | Open cable; lamp condition unknown | Isolated cable replacement | Supply restored, light still absent |
| Same beacon after first repair | Healthy lamp supply, dark output | Isolated lamp continuity test | Open load confirmed |
| Confirmed second fault | Open lamp as well as the earlier cable break | Isolated lamp replacement | 9 V supply and visible light |
Reflection
My first diagnosis was useful but incomplete. Assuming it explained the entire symptom would have stopped the investigation too early. The failed output check changed what I needed to test, without erasing the evidence that justified the cable replacement. In a new case I would read whether its rules permit multiple faults, diagnose from its own trace and check the original symptom after every repair. This example does not establish that the assigned one-fault circuit has two defects.
Limits
These are idealised authored model readings, not measurements from constructed hardware. A continuity check is performed only in the model's isolated state. The record establishes this fictional apparatus's behaviour and does not certify work on an arbitrary physical circuit.
Named output: circuit-diagnosis. Assistance: complete narrated worked example.
Method to carry forward
Repair only what the evidence supports, then test the original symptom again.
This example has two simultaneous faults; the assigned model has one. Use its observed trace, not this cable-and-lamp answer.
The complete example explains one defensible approach. In your own challenge, select observations and tests from the supplied rules, keep your prediction separate from the result, and justify both the checks you perform and those you omit.
Complete transcript and decisions · readable without JavaScript
Before we begin · expected task and evidence
I must restore one fictional nine-volt beacon. This case allows more than one fault at the same time, unlike the assigned lab's single-fault cases. I will locate a supported supply fault, make a controlled repair, test the original symptom, and continue if the beacon still fails. My diagnosis must preserve the incomplete first repair as well as the final working result. The method we are practising is: Repair only what the evidence supports, then test the original symptom again.. Our field objective is: Restore the conservatory beacon and hand its two-fault diagnosis to the service team. Repairing the open cable restores supply but leaves the same beacon dark. I will perform the supported intervention and handover. You can pause, mute, replay, or take control at any point. The captions show the same explanation.
1. Read the case rule and initial trace
What I need to do: Step 1. Read the case rule and initial trace. I read the rule that several faults may coexist. I power the model for voltage readings and record each point. A missing supply means I cannot yet conclude that the lamp itself is healthy.
Supplied context: The case card says this one beacon may contain several faults at once. With power on, source and fuse outputs read 9 V; cable output and beacon supply read 0 V. The dark lamp cannot yet tell us whether its own load is healthy because supply is missing.
Watch my actions: For "Source voltage", I enter 9 V. I set "Power on for voltage measurement" to yes. For "How many faults may coexist?", I choose "More than one fault may coexist". I check the demonstrated result.
What I observed: The trace establishes a supply interruption without declaring that it is the only defect. A known supply break can hide a second defect. The assigned single-fault assumption does not apply to this example.
Why: A known supply break can hide a second defect. The assigned single-fault assumption does not apply to this example.
Decision: Record the powered source and the case rule before diagnosing.
- Source voltage: 9 V
- Power on for voltage measurement: Yes
- How many faults may coexist?: More than one fault may coexist
Result: The trace establishes a supply interruption without declaring that it is the only defect.
Common mistake: Importing the assigned lab’s one-fault guarantee would make the first diagnosis falsely exhaustive.
2. Locate the first supported fault
What I need to do: Step 2. Locate the first supported fault. I compare the healthy fuse output with the zero cable output. This supports a cable fault, while the load remains untested. I state that limit before changing a component.
Supplied context: The fuse output is 9 V while the cable output is 0 V. That comparison supports an open cable. The demonstrator records a first diagnosis, not a claim that every other component is working.
Watch my actions: For "First supported open component", I choose "cable". For "What is still unresolved?", I choose "Is the lamp also faulty?". I check the demonstrated result.
What I observed: The cable fault is supported while the load remains an open question. A diagnosis should say what the measurement discriminates. A downstream unpowered load remains untested.
Why: A diagnosis should say what the measurement discriminates. A downstream unpowered load remains untested.
Decision: Identify the supported first fault and the limit of this conclusion.
- First supported open component: cable
- What is still unresolved?: Is the lamp also faulty?
Result: The cable fault is supported while the load remains an open question.
Common mistake: Finding one real fault does not establish that no other fault exists.
3. Replace the cable while isolated
What I need to do: Step 3. Replace the cable while isolated. I isolate power and replace only the cable justified by the trace. I keep the lamp unchanged so the next check can tell me what the cable repair actually achieved.
Supplied context: The demonstrator switches the model source off and replaces only the cable supported by the trace. The lamp has not been tested or replaced. The original powered readings stay in the record.
Watch my actions: I set "Source powered during replacement" to no. For "Replace first", I choose "Cable only". I check the demonstrated result.
What I observed: The cable is replaced without treating the untested lamp as repaired. Changing only the diagnosed component makes the next verification informative.
Why: Changing only the diagnosed component makes the next verification informative.
Decision: Isolate the model and choose the evidence-backed first replacement.
- Source powered during replacement: No
- Replace first: Cable only
Result: The cable is replaced without treating the untested lamp as repaired.
Common mistake: Replacing everything would conceal which change resolved which symptom.
4. Let failed verification change the diagnosis
What I need to do: Step 4. Let failed verification change the diagnosis. I restore power to the same beacon. All supply points now read nine volts, but the lamp is still dark. I record a successful supply repair and an unsuccessful whole-system check together.
Supplied context: Power returns to the same beacon. Source, fuse, cable output and lamp supply now all read 9 V, yet the lamp stays dark. The cable repair restored supply but did not fix the original symptom. The demonstrator keeps the first diagnosis and opens a second investigation.
Watch my actions: I set "Restore power" to yes. For "Observed output after cable repair", I choose "9 V present; lamp still dark". I set "Whole beacon verified working" to no. I check the demonstrated result.
What I observed: The record preserves a valid cable repair and a failed complete-system verification. A successful intermediate repair and an unsuccessful whole-system check can both be true.
Why: A successful intermediate repair and an unsuccessful whole-system check can both be true.
Decision: Restore power, report the remaining symptom and decide whether the job is complete.
- Restore power: Yes
- Observed output after cable repair: 9 V present; lamp still dark
- Whole beacon verified working: No
Result: The record preserves a valid cable repair and a failed complete-system verification.
Common mistake: Counting healthy supply as success would leave the original dark-beacon problem unresolved.
5. Test the newly exposed load fault
What I need to do: Step 5. Test the newly exposed load fault. Healthy supply with a dark output gives me a new question about the lamp. I isolate power and check its continuity. The open result identifies a second defect in the same beacon.
Supplied context: The healthy 9 V supply and still-dark output make a load check informative. The demonstrator isolates the source and tests lamp continuity. The authored result is open: the same beacon had an open lamp as well as the cable break.
Watch my actions: For "Next test", I choose "Isolate; test lamp continuity". I set "Power during continuity check" to no. I check the demonstrated result.
What I observed: Isolated continuity identifies the second fault without invalidating the earlier cable diagnosis. Restoring one prerequisite can expose a defect that the original measurements could not distinguish.
Why: Restoring one prerequisite can expose a defect that the original measurements could not distinguish.
Decision: Choose the next discriminating test and its required power state.
- Next test: Isolate; test lamp continuity
- Power during continuity check: No
Result: Isolated continuity identifies the second fault without invalidating the earlier cable diagnosis.
Common mistake: Repeating the source reading adds no evidence about the load itself.
6. Repair the second fault and verify the whole beacon
What I need to do: Step 6. Repair the second fault and verify the whole beacon. With power isolated, I replace the confirmed open lamp. I restore power and verify both supply and light. I preserve the first failed verification because it explains why the second test was necessary.
Supplied context: With power still isolated, the demonstrator replaces the confirmed open lamp. Restored power now gives 9 V at every supply node and visible light. The final record retains both faults, the incomplete first repair and the final verification; no second beacon or reset was introduced.
Watch my actions: For "Second isolated replacement", I choose "Lamp". I set "Restore power after lamp replacement" to yes. For "Diagnostic lesson", I choose "Two faults; verify both repairs". I check the demonstrated result.
What I observed: The same beacon now meets its supply and light requirements after two evidence-backed repairs. Completion follows a check of the original system requirement after all supported repairs, not simply the first successful intervention.
Why: Completion follows a check of the original system requirement after all supported repairs, not simply the first successful intervention.
Decision: Choose the second replacement, restore power and state what the complete trace established.
- Second isolated replacement: Lamp
- Restore power after lamp replacement: Yes
- Diagnostic lesson: Two faults; verify both repairs
Result: The same beacon now meets its supply and light requirements after two evidence-backed repairs.
Common mistake: Neither a one-fault assumption nor an “always two faults” rule transfers safely to a different published case.
Performing the field operation
All chapter evidence checks are complete. I return to the mission station and activate the repaired beacon. I am putting the verified solution into effect, then checking what changes.
I collect Beacon repair and verification record. The verified intervention released this package. I now carry it through the marked handover route.
I carry Beacon repair and verification record to Beacon service cabinet. I confirm this checkpoint before continuing so the handover trace records the route actually followed.
I carry Beacon repair and verification record to Service-team dispatch. I confirm this checkpoint before continuing so the handover trace records the route actually followed.
At the receiving station, I complete the service handover. I check the receipt before calling the field operation complete.
My observations and finished submission
My initial trace was nine, nine, zero, zero volts across source, fuse, cable and lamp supply. I diagnosed and replaced the cable while isolated. That restored nine volts throughout, but the same beacon stayed dark. The first diagnosis was useful, not complete. An isolated continuity test then identified an open lamp. After replacing it and restoring power, I verified nine volts and visible light. My record keeps both faults, the failed intermediate verification and the final result. I will use the assigned case's own one-fault rule and measurements rather than assume every circuit shares this example's two defects. Repair only what the evidence supports, then test the original symptom again. Open "Read the finished work" or download the complete example to inspect the evidence and explanation together. This example has two simultaneous faults; the assigned model has one. Use its observed trace, not this cable-and-lamp answer.
The complete submission is available in Read the finished work above and as a Markdown download.