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 357 on a CONMED System 2450 / 5000 Series electrosurgical unit when the monitor senses output power while the dial power setting is 0 W. This condition may indicate an accessory issue, setting problem, calibration problem, false power sensing issue, or internal RF output/control failure.

Because this error involves possible sensed RF output when output should be zero, it should be treated as a patient safety concern until the ESU is removed from use, evaluated, and verified safe before return to service.

Step-by-Step Troubleshooting

Ensure Patient Safety First

• Remove the ESU from patient use immediately if Err 357 appears during setup, activation, or clinical use.
• Do not continue using the generator with an unresolved sensed-power fault.
• Have staff switch to another approved ESU if electrosurgery is still needed.
• Disconnect the affected ESU from the patient circuit when safe to do so.
• Label the unit for Clinical Engineering evaluation if the error is active or repeatable.

Verify the Reported Error and Behavior

• Power the unit on in a safe, non-patient-use setting.
• Confirm the exact displayed error is Err 357.
• Ask clinical staff when the error occurred: startup, idle, activation, after changing settings, or after connecting an accessory.
• Note whether the ESU alarms, disables output, fails POST, or only faults intermittently.
• Document whether the error can be reproduced.

Check the Power Setting and Front Panel Controls

• Confirm the dial or power setting is actually set to 0 W when the fault occurs.
• Inspect the power adjustment controls for sticking, contamination, physical damage, or erratic behavior.
• Move the control through its normal range and return it to 0 W.
• Power cycle the ESU and check whether Err 357 returns.

Remove External Accessories

• Disconnect footswitches, handpieces, active pencils, bipolar accessories, dispersive electrode cables, and output cables.
• Inspect accessories for fluid contamination, stuck activation buttons, bent pins, damaged insulation, or incorrect connection.
• Power the ESU on with all accessories removed.
• Reconnect accessories one at a time only in a controlled, non-patient-use setting.
• If the fault follows one accessory, remove that accessory from service and retest with a known-good equivalent.

Inspect External Connections and Physical Condition

• Inspect ESU output ports for debris, fluid intrusion, burns, damaged contacts, or loose connectors.
• Check the power cord, plug, and AC connection for visible damage.
• Verify the unit is connected to a properly grounded hospital-grade outlet.
• Look for signs of overheating, odor, liquid spill, impact damage, or prior repair labels.

Power Cycle and Recheck

• Turn the ESU off.
• Disconnect it from AC power briefly.
• Reconnect power and restart the unit.
• Confirm whether Err 357 returns during POST, idle state, or activation testing.
• If the error repeats with no accessories connected, treat the issue as device-related.

Perform Bench Testing Only If Qualified and Equipped

• Move the ESU to a controlled bench environment.
• Use an appropriate ESU analyzer or approved fixed test load.
• Configure the system for approved test mode if available to Clinical Engineering.
• Measure output power into the fixed load while verifying whether any power is present when the commanded setting is 0 W.
• Compare measured output behavior to expected operation.
• Do not return the unit to service unless it passes required performance and safety checks.

Recalibrate if Appropriate

• If your department is authorized and equipped to perform calibration, recalibrate the system according to approved service procedures.
• After calibration, repeat output testing into a fixed load.
• Confirm Err 357 does not return.
• Verify output readings remain accurate across required modes and settings before return to service.

Evaluate Likely Internal Failure Areas

• If Err 357 persists after external checks, accessory isolation, power cycling, and calibration, suspect an internal failure.
• Possible internal areas include monitor voltage/current sensing circuits.
• Possible internal areas include RF Controller sensing circuits.
• Possible internal areas include the high-voltage power supply.
• Possible internal areas include the RF Amplifier.
• Possible internal areas include the RF Transformer board, RF Output board, or Controller assembly.

If the Problem Persists

If Err 357 remains after external causes, accessories, power setting issues, outlet concerns, and common setup problems have been ruled out, remove the ESU from service.

Label the device Out of Service.

Send it for repair or advanced bench evaluation.

Do not continue repeated clinical testing with a generator that reports sensed power while the commanded power setting is 0 W. Persistent Err 357 strongly suggests an internal output control, sensing, HVPS, RF amplifier, RF output, or controller-related failure.

Clinical Use Tip

Never troubleshoot an ESU with an unresolved power-sensing fault on an active patient. Move the patient or procedure to a backup ESU first, then evaluate the affected generator in a safe bench or non-patient-care setting.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"User reported CONMED System 2450 / 5000 Series ESU displayed Err 357. Error indicates monitor sensed output power while dial power setting was 0 W. Unit removed from patient use for evaluation."

Cause

What was observed during troubleshooting.

Example:
"Confirmed Err 357 during evaluation. Power setting, accessories, external connections, and power source were checked. Fault persisted with accessories removed, indicating likely internal output sensing, RF control, HVPS, RF amplifier, RF output, or controller-related failure."

Resolution

What action was taken.

Example:
"Removed ESU from service and labeled Out of Service. Unit sent for repair or advanced bench evaluation. Safety and performance testing required 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 357 should be treated seriously because the ESU is reporting sensed power when output should be zero. Good troubleshooting starts with patient safety, confirms the error, rules out settings and accessories, then moves to controlled bench testing, calibration, and repair escalation when needed. Clear CCR documentation protects the patient, the technician, and the equipment history.

That is successful troubleshooting.