CONMED System 2450 / 5000 Series

Asset Type

Electrosurgical Unit (ESU)

Manufacturer

CONMED

Model

System 2450 / 5000 Series

What This Guide Helps With

This guide helps troubleshoot Err 373 on a CONMED System 2450 / 5000 Series electrosurgical unit when the generator fails POST because the damping circuit is not detected. This condition can prevent safe RF output operation and should be treated as a serious generator fault until the device is evaluated and tested.

Step-by-Step Troubleshooting

Ensure Patient Safety First

• Remove the ESU from patient use if Err 373 appears during startup, setup, or clinical use.
• Stop use of the generator and notify clinical staff that the ESU failed self-test.
• Provide a replacement ESU if the procedure requires electrosurgery.
• Do not attempt to continue clinical use after a POST failure.

The patient should not be exposed to an ESU with an unresolved RF control or damping fault. A damping circuit fault may affect RF output control, especially during coagulation modes.

Verify the Reported Error and Behavior

• Power the unit on and confirm the displayed error is Err 373.
• Record whether the error occurs immediately during POST or only after activation.
• Confirm whether the generator completes startup or remains locked out.
• Ask clinical staff whether the issue occurred in Spray Coag, Standard Coag, or during startup only.
• Check for any other errors before or after Err 373.

This confirms the issue is a true system-reported damping circuit fault and not a user setup issue, accessory problem, or unrelated activation complaint.

Check Power Source and Basic Setup

• Verify the ESU is connected to a known-good hospital-grade outlet.
• Confirm the power cord is fully seated and undamaged.
• Check for loose connection, damaged plug, burnt smell, heat, or intermittent power.
• If safe and appropriate, test the unit from another verified outlet.

Stable input power should be confirmed before assuming an internal control or RF circuit failure.

Inspect the Unit Externally

• Inspect the front panel, rear panel, output ports, and accessory receptacles.
• Look for fluid intrusion, cracked housing, impact damage, debris, bent pins, or contamination.
• Confirm no accessories, pencils, footswitches, or adapters are stuck, damaged, or partially connected.
• Disconnect external accessories and retry startup.

No external damage or accessory issue should explain the POST failure before the unit is escalated for bench-level evaluation.

Power Cycle and Recheck

• Turn the ESU off.
• Disconnect power briefly.
• Reconnect power and restart the unit.
• Observe whether Err 373 returns during POST.

A temporary logic fault may clear, but a repeatable POST failure strongly suggests the unit is detecting a real internal damping circuit or control problem.

Isolate From User Setup

• Confirm the error occurs without patient accessories connected.
• Confirm the issue is not tied to one handpiece, footswitch, return electrode cable, or adapter.
• If the unit passes POST with accessories disconnected, reconnect accessories one at a time and retest.

The damping circuit is internal to the RF output/control path, but external setup should still be ruled out before repair escalation.

Configure for Bench Evaluation or Test Mode

• Remove the unit from clinical use and move it to a controlled bench area.
• Configure the system for appropriate test mode only if trained, authorized, and equipped to do so.
• Use proper ESU analyzer/load setup before activation testing.
• Do not activate RF output without an approved load and safe test setup.

Err 373 involves RF drive and damping timing. Troubleshooting should not be performed casually in a clinical area.

Verify Damping-Related Operation During Coag Modes

• In test mode, activate the unit in Spray Coag or Standard Coag using the proper fixed load/test setup.
• Verify whether the damping function is being detected during RF activation.
• The expected service-level behavior is that the RFDAMP_DR signal switches high immediately before each RF drive pulse and switches low after each RF drive pulse.
• If the damping signal does not switch correctly, suspect the RF Amplifier damping circuitry or Controller drive/control path.

Err 373 means the system expected to detect damping behavior during POST but did not. This points toward the RF Amplifier damping circuitry or Controller assembly.

Inspect Internal Connections Only at an Appropriate Service Level

• If authorized, inspect accessible internal harnesses and connectors related to the RF Amplifier and Controller assemblies.
• Look for loose connectors, damaged wiring, poor seating, contamination, or signs of overheating.
• Reseat only approved connectors if allowed by facility procedure and service capability.

A missing damping signal may be caused by an actual circuit failure, but connector issues should be ruled out before replacing assemblies.

Determine Whether the Fault Is Device-Related

• If Err 373 remains after power, accessory, setup, and connection checks, treat the issue as an internal ESU failure.
• Suspect failure in the RF Amplifier damping circuitry or the Controller assembly.
• Do not return the ESU to service based only on intermittent clearing unless full functional and safety testing passes.

Err 373 is not a normal user-correctable alarm. Persistent failure indicates the ESU cannot verify a required RF damping function.

Stop When Resolved

• Repeat startup testing.
• Confirm Err 373 no longer appears.
• Perform required ESU performance testing.
• Perform electrical safety testing if required by facility policy after repair or service.
• Confirm RF output operation using an approved ESU analyzer and load.
• Document the final status clearly.
• Return the device to service only after all required checks pass.

The ESU should pass POST, function normally, and be confirmed safe before return to clinical use.

If the Problem Persists

If Err 373 continues after external checks, power cycling, accessory isolation, and appropriate bench evaluation, external and common causes have been ruled out.

Persistent Err 373 strongly indicates an internal RF damping circuit, RF Amplifier assembly, or Controller assembly failure.

• Remove the device from service.
• Label it Out of Service.
• Send it for repair or bench evaluation.
• Repair or replace the RF Amplifier assembly or Controller assembly as appropriate.
• Fully performance-test the ESU before return to service.

Knowing when to stop is proper troubleshooting. An ESU with an unresolved POST damping circuit failure should not be placed back into patient use.

Clinical Use Tip

Never troubleshoot an ESU with Err 373 on an active patient. Move the patient or procedure to a backup generator first, then remove the affected ESU from clinical use. An unresolved RF output control fault can create unpredictable surgical performance and should be treated as a patient safety issue.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"CONMED System 2450 / 5000 Series ESU reported Err 373 during startup. Unit failed POST with damping circuit not detected and was unavailable for clinical use."

Cause

What was observed during troubleshooting.

Example:
"Err 373 confirmed during power-on testing. External accessories disconnected and power source checked. Error persisted, indicating likely internal damping circuit, RF Amplifier, or Controller assembly failure."

Resolution

What action was taken.

Example:
"Removed ESU from service and labeled Out of Service. Sent for bench repair/evaluation. RF Amplifier damping circuitry and Controller assembly to be evaluated before return to service."

Helpful Details to Include (If Known)

• Alarm behavior
• Accessories swapped
• Power behavior
• Environmental factors
• Indicator lights
• Final device status

Final Thought

Err 373 should be treated as a serious ESU POST failure because the generator is reporting that damping was not detected. Start with patient safety, confirm the exact error, rule out simple external causes, then move logically toward internal RF/control troubleshooting. If the fault persists, remove the device from service and escalate for repair. Clear CCR documentation protects the patient, the technician, and the facility.

That is successful troubleshooting.