CoolArc160 Low-OCV Drill

Drill Goal

• teach the trainee to prove clamp, branch power, and fan behavior before internal repair
• teach the correct move from measurement card to packet to opening map

Starting Scenario

• Model: CoolArc160
• Complaint: low OCV, weak arc strike, and fan slows after a short run
• Arrival condition: clamp is visibly worn and the tech knows the unit may be an older revision

Expected Document Sequence

1. CoolArc160 measurement card
2. CoolArc160 job packet
3. CoolArc160 board opening map only if the complaint stays machine-side

Success Criteria

• the trainee says the first proof step is clamp, branch power, and fan behavior
• the trainee uses bus and auxiliary-supply logic before naming a board
• the trainee recognizes revision context before treating CN104 and CN108 as interchangeable

Common Misses

• jumping straight to inverter-board suspicion
• ignoring the possibility of fan-revision or polarity mismatch
• skipping the current-path proof because the symptom sounds electrical

Debrief

• The key lesson is that low OCV alone does not justify board replacement on this model.
• Internal opening is justified only after the current path, fan branch, and support-power behavior are already bounded.