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What This Guide Helps With
This guide helps troubleshoot Err 117 on a CONMED System 2450 / 5000 Series electrosurgical unit when the generator detects a low 5.0 V supply condition. This fault can affect controller operation, monitoring circuits, display behavior, activation response, and startup safety checks.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Remove the ESU from patient use if Err 117 appears during setup, startup, or clinical use.
- Stop use of the generator and notify clinical staff that the ESU has a system power fault.
- Provide a known-good replacement ESU before the procedure continues.
- Do not allow use of the generator with an unresolved voltage-related error.
Verify the Reported Error and Behavior
- Power the ESU on in a safe, non-patient-care setting.
- Confirm the exact displayed error is Err 117.
- Observe whether the error appears immediately at startup, during POST, intermittently, or during activation.
- Check for related symptoms such as failed startup, display issues, keypad issues, no activation, unexpected resets, or other power-related faults.
Check the AC Power Source First
- Verify the ESU is plugged into a known-good hospital-grade outlet.
- Inspect the power cord for damage, loose fit, bent blades, cuts, or signs of overheating.
- Confirm the outlet is not controlled by a switched circuit or overloaded power strip.
- If needed, test the ESU from another known-good outlet.
Inspect the Power Cord and External Condition
- Check the power cord connection at the ESU if the cord is detachable.
- Inspect the rear panel, power entry area, fuse holder, and cord strain relief.
- Look for physical damage, liquid intrusion, burned smell, discoloration, or signs of impact.
- Do not open the unit for deeper inspection unless qualified and following facility procedures.
Power Cycle and Recheck the Error
- Turn the ESU off.
- Disconnect it from AC power for a short period.
- Reconnect it to a known-good outlet.
- Power the unit back on and observe whether Err 117 returns.
- If Err 117 clears and the unit passes startup checks, complete required functional testing before returning it to service.
Remove Accessories and Retest
- Remove connected handpieces, footswitches, return electrode cables, bipolar cables, and other accessories.
- Power cycle the ESU with no accessories connected.
- Observe whether Err 117 still appears.
- Reconnect accessories one at a time only after the generator powers on normally.
Check Basic Front Panel Behavior
- Confirm the display powers normally before the error appears.
- Check whether buttons respond before the fault occurs.
- Listen for normal startup tones if applicable.
- Observe whether the unit resets, freezes, dims, or shuts down.
Escalate to Bench Evaluation
- After external power, accessories, and basic setup are ruled out, treat Err 117 as an internal supply or sensing issue.
- Verify the low-voltage power supply output during bench evaluation.
- Verify Controller ADC reference voltages are approximately 2.5 V.
- If the low-voltage power supply output is out of limits, repair or replace the power supply according to facility procedure.
- If supply voltage is within limits but Err 117 remains, suspect the Controller assembly or voltage monitoring circuitry.
- After repair, complete required functional testing, ESU output verification, and electrical safety testing before returning the unit to service.
If the Problem Persists
If Err 117 continues after verifying the AC outlet, power cord, accessories, external condition, and power cycling, the common external causes have been ruled out.
A persistent Err 117 strongly indicates an internal low-voltage power supply problem or Controller assembly voltage monitoring fault.
The device should be removed from service, labeled Out of Service, and sent for repair or bench evaluation.
Clinical Use Tip
Never troubleshoot this error on an active patient. Move the patient or procedure to a backup ESU first. A low 5.0 V logic supply fault can affect system control, monitoring, display function, and activation reliability.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"CONMED System 2450 / 5000 Series ESU displayed Err 117, 5.0 volt too low, during startup. Unit removed from service due to power supply-related system fault."
Cause
What was observed during troubleshooting.
Example:
"Verified Err 117 was repeatable. External AC outlet, power cord, accessories, and basic setup were checked. Fault indicates low 5.0 V supply condition or Controller voltage monitoring issue."
Resolution
What action was taken.
Example:
"Removed ESU from clinical use and labeled Out of Service. Unit requires bench evaluation of low-voltage power supply output and Controller ADC reference voltages. Repair to include power supply replacement if output is out of limits or Controller assembly replacement if supply voltage is normal and fault persists."
Helpful Details to Include (If Known)
- Alarm behavior
- Accessories swapped
- Power behavior
- Environmental factors
- Indicator lights
- Final device status
Final Thought
Err 117 should be treated as a system power integrity fault, not a normal user setup issue. Start with patient safety, confirm the error, rule out simple external causes, then escalate appropriately when the low-voltage supply or Controller assembly is suspected. Clear documentation helps show that the fault was handled logically and safely.
That is successful troubleshooting.