Electrosurgical units · CMC family

Codman CMC III ESU: troubleshooting and error codes

The ServiceForge knowledge base holds 11 documented symptoms for the Codman CMC III ESU, with 12 ranked causes, 20 diagnostic checks with test points and expected values, and 0 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Calibration: CMC III ESU power output high voltage

Verify electrosurgical generator output wattage in cut and coagulation modes matches specifications across different load impedances using analyzer

Ranked causes

1. Initial setup verification required (unknown)
2. Cut mode power output verification (unknown)

First check

Visual inspection for damage

Test point: Connectors, power cord, footswitch, cable, main unit/irrigator cable
Expected: No visible damage or faults

4 more checks with pass and fail actions, 4 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Coagulation output

Verify coagulation wattage output against power setting dial with 125 ohm load and high sense

Ranked causes

1. Output calibration drift or initial verification needed (unknown)

First check

Measure coagulation output wattage

Test point: Coagulation output terminals
Expected: 40-50 watts peak at maximum power setting into 125 ohms W, 40-50 W
Tools: ESU analyzer set to 125 ohms high sense

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Cut output

Verify cutting wattage output at 50 and 400 ohm loads against power setting

Ranked causes

1. Cut output calibration drift or initial verification needed (unknown)

First check

Measure cut output at 50 ohms load

Test point: Cut output terminals
Expected: Output proportional to power setting per appendix chart at 50 ohms
Tools: ESU analyzer set to 50 ohms

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Cutting output

Verify cutting power output at specified loads matches expected display relationship

Ranked causes

1. Calibration check at rated loads (common)

First check

Measure cut output at 50 ohms

Test point: Cut output 50 ohms
Expected: Per appendix chart

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Irrigator function

Verify irrigator rollers operate when main unit is keyed

Ranked causes

1. Irrigator operational check (common)

First check

Key main unit and observe irrigator

Test point: Irrigator rollers
Expected: Rollers turn for several seconds then stop

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Power output verification

Verify coagulation and cutting power output matches expected values at analyzer load settings

Ranked causes

1. DAC calibration drift or incorrect settings (unknown)

First check

Measure coagulation output at 125 ohms load with high sense

Test point: Analyzer input
Expected: 40-50 watts peak
Tools: ESU analyzer

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Safety check: Bipolar output insulation patient safety

Verify resistance between case and bipolar output contacts exceeds minimum

Ranked causes

1. Insulation integrity check (common)

First check

Measure insulation resistance to bipolar contacts

Test point: Case to bipolar output
Expected: > 10 megohms MΩ, > 10
Tools: Insulation resistance tester

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Safety check: Bipolar output isolation caution

Verify case to bipolar output contact resistance is adequate

Ranked causes

1. Insulation breakdown between case and output (rare)

First check

Measure case to bipolar output contact resistance

Test point: Case ground to bipolar output contact
Expected: Greater than 10 megohms, >10 megohms
Tools: Ohmmeter or safety tester

Safety check: Ground lead resistance patient safety

Verify ground lead resistance is within specification

Ranked causes

1. Ground circuit integrity check (common)

First check

Measure ground lead resistance

Test point: Ground lead
Expected: < 0.15 ohms Ω, < 0.15
Tools: Safety tester

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Safety check: Line leakage current patient safety

Verify line leakage current with ground open is within safe limits

Ranked causes

1. Safety compliance verification (common)

First check

Measure line leakage with ground open

Test point: Line leakage
Expected: < 50 µA, < 50
Tools: Safety tester

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Verify irrigator function

Check that irrigator rollers engage when main unit is keyed

Ranked causes

1. Irrigator malfunction or loose connection (unknown)

First check

Activate main unit and observe irrigator

Test point: Irrigator rollers
Expected: Rollers turn for several seconds then stop

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.