Troubleshoot Electrical Faults with Evidence

Electrical troubleshooting should get quieter as it gets better.

Randomly reseating everything can make an intermittent fault disappear, but it also destroys the evidence that could explain it.

Build a fault record before the fix

Record:

• exact symptom;
• operating condition;
• which systems were affected;
• which systems remained normal;
• device lights/status if meaningful;
• Driver Station or device faults;
• voltage/current evidence if available;
• what changed immediately before the failure.

That snapshot matters because some faults vanish once the robot is moved back to the pit.

Fault pattern 1: one device fails

Likely investigation area:

• its branch power;
• its connector;
• its configuration;
• its local CAN connection;
• its motor/sensor;
• its software mapping.

Fault pattern 2: several neighboring CAN devices fail

Investigate shared communication path and connectors before assuming simultaneous device failures.

Fault pattern 3: many systems reset under load

Investigate battery, main connections, voltage sag, high-current loads, and mechanical binding.

Fault pattern 4: intermittent failure after impacts

Mechanical strain on electrical connections becomes a serious suspect.

Wires and connectors live on a moving competition machine. Routing, strain relief, service loops, connector retention, and physical protection affect reliability.

A controlled diagnostic sequence

Use this sequence on a supplied fault or a real supervised issue:

1. reproduce or precisely describe symptom
2. identify shared dependencies
3. inspect status/log evidence
4. de-energize before physical connection work
5. inspect one suspected boundary
6. make one change
7. restore power for controlled test
8. record result

One change at a time. Otherwise you lose causality.

Your fault-isolation record

Create a table with at least three hypotheses:

Finish with one paragraph explaining why the final diagnosis is stronger than the alternatives.

If no hardware fault is available, use this case:

The robot drives normally for twenty seconds, then several high-current mechanisms slow down. The Driver Station reports low-voltage events during simultaneous drivetrain acceleration and elevator movement.

Your job is not to “fix” the case instantly. Your job is to design the evidence collection that would isolate electrical, mechanical, and software contributors.

Inspection mindset

Competition inspection checks compliance, but teams should self-inspect long before an event.

Your electrical map should be readable by someone who did not wire the robot. Labels should mean something. Critical components should be accessible. Connections should be protected from predictable motion and impact.

A robot that only one person can understand is a reliability risk.

Add your power tree, CAN map, and fault record to the Unit 4 evidence package.