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What This Guide Helps With
Troubleshooting an unresponsive touchscreen, frozen user interface, stuck rotary knob, or inability to select, adjust, or confirm settings.
Step-by-Step Troubleshooting
1. Ensure Patient Safety First
Do not perform extended troubleshooting while the Perseus is supporting an active patient.
If the controls become unresponsive during a case:
- Have anesthesia staff secure ventilation and gas delivery.
- Move the patient to another verified anesthesia machine when clinically appropriate.
- Ensure a functional manual resuscitator and substitute patient monitoring are immediately available.
- Follow the facility’s anesthesia-machine failure procedure.
Drager’s guidance for a screen or user-interface failure includes manual ventilation, emergency oxygen delivery, checking the vaporizer setting, and providing substitute monitoring.
Expected: Patient care no longer depends on equipment with unreliable controls.
If patient safety and alternate equipment are established, continue troubleshooting off patient.
2. Confirm the Exact Failure Mode
Determine precisely what is unresponsive:
- Screen is blank or displaying an image
- Entire touchscreen or only one screen area is affected
- Rotary knob turns but values do not change
- Rotary knob changes values but will not confirm when pressed
- Knob is physically stuck or difficult to move
- Hard keys respond normally
- Alarm message such as Rotary knob stuck is present
- Failure occurred during startup, self-test, Standby, or operation
The touchscreen calls up functions, while the rotary knob selects and confirms settings. A failure of one control may therefore appear different from a complete user-interface freeze.
Expected: The complaint is narrowed to touchscreen input, knob rotation, knob confirmation, display failure, or complete interface failure.
3. Inspect the Touchscreen and Rotary Knob
With the machine safely out of clinical use, inspect for:
- Cracked or damaged screen glass
- Moisture, disinfectant residue, gel, adhesive, or debris
- A screen covering or label contacting the active display area
- Residue around the rotary knob
- A knob that remains depressed or binds while turning
- Evidence of liquid entering around the controls
Clean and dry the external controls using the facility-approved method and Drager-compatible products. Do not spray liquid directly into the screen or knob assembly.
Drager warns that liquid entering the machine can cause malfunction or equipment damage.
Expected: The screen is clean and dry, and the knob turns and presses freely.
If normal response returns, complete functional testing before returning the machine to service.
4. Verify That the Control Is Available
Place the machine in Standby and test a non-therapy menu or setting.
Observe the displayed control color:
- Gray controls may be unavailable in the current operating state.
- Yellow indicates that a selection requires confirmation.
- Pressing the rotary knob should confirm the selected setting.
- A pending selection may reset if it is not confirmed.
This distinguishes a genuinely failed control from a function that is unavailable or awaiting confirmation.
Expected: An available control responds to touch, the knob changes the value, and pressing the knob confirms it.
If only certain functions are unavailable, verify the current mode and configuration before assuming hardware failure.
5. Check External Power and System Status
Verify:
- Power cord is fully seated at the machine and receptacle
- Receptacle provides stable facility power
- Mains-power indication is present
- Battery status is normal
- No power-supply alarms are displayed
- The secondary status display remains active and readable
Correct loose connections or an external power problem before evaluating the user interface further.
Expected: The machine has stable AC power and no abnormal power indications.
If correcting power restores control response, complete the system test and stop.
6. Address a Rotary Knob Stuck Alarm
If Rotary knob stuck is displayed, verify that the knob is not being continuously pressed by residue, damage, or an attached object.
In an off-patient test environment:
- Press and release the knob.
- Turn it slowly in both directions.
- Repeat several times without applying excessive force.
Drager identifies a stuck key or a knob pressed longer than ten seconds as possible causes. If the condition persists, settings may no longer be adjustable.
Expected: The alarm clears and the knob moves, selects, and confirms normally.
If the knob remains stuck or the alarm returns, stop and remove the machine from service.
7. Perform a Controlled Restart
Only restart after the machine is disconnected from the patient and alternate equipment is available.
- Use the normal shutdown procedure when the controls permit.
- If the machine is completely unresponsive, follow the approved device-switch shutdown procedure.
- Restore power and observe the complete startup sequence.
- Record any error, warning, or abnormal startup behavior.
Drager directs the user to switch off the device when it no longer responds to operation.
Expected: The Perseus starts normally and both controls respond consistently.
If a restart resolves the freeze, continue with system testing rather than immediately returning the machine to service.
8. Complete the System Test and Functional Verification
Perform the approved pre-use or system test.
Verify:
- Touch response in several screen locations
- Accurate selection of displayed controls
- Smooth rotary knob movement
- Reliable confirmation when the knob is pressed
- No stuck-knob or user-interface alarm
- Stable display without freezing, flickering, or unintended selections
- Correct response through several repeated control changes
Do not test therapy-setting changes on a patient.
Expected: The system test passes and both controls remain reliable through repeated operation.
If the interface fails again, the machine is not suitable for clinical use.
If the Problem Persists
If cleaning, mode verification, power checks, rotary-knob testing, restart, and system testing do not restore dependable operation, common external causes have been ruled out.
The failure may involve the touchscreen, rotary-knob assembly, user-interface electronics, internal cabling, or system software.
The device should be:
- Removed from service
- Labeled Out of Service
- Replaced with a verified anesthesia machine
- Sent for authorized repair or bench evaluation
- Referred to Drager or qualified service personnel
Do not open the display housing or attempt board-level repair without the proper service authorization, documentation, and test equipment.
Knowing when to stop is proper troubleshooting.
Clinical Use Tip
Never evaluate intermittent touchscreen or rotary-knob operation during active anesthesia. A control that works only after repeated attempts cannot be considered dependable for therapy changes.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Anesthesia staff reported that the Perseus touchscreen would not respond and the rotary knob would not confirm settings during the pre-use checkout."
Cause
What was observed during troubleshooting.
Example:
"External power and control surfaces were acceptable, but the touchscreen and rotary knob remained unresponsive after a controlled restart, indicating a probable internal user-interface fault."
Resolution
What action was taken.
Example:
"Removed the anesthesia machine from service, applied an Out of Service label, documented the failed functional test, and routed the unit for authorized Drager evaluation."
Helpful Details to Include (If Known)
- Active patient involved or pre-use failure
- Touchscreen blank, frozen, partially responsive, or completely unresponsive
- Rotary knob turns normally
- Rotary knob confirms when pressed
- Rotary knob stuck alarm observed
- Screen or knob contamination found
- Evidence of liquid exposure
- AC outlet and power cord verified
- Battery and mains indicators normal
- Restart performed
- System test result
- Failure intermittent or repeatable
- Final device status
Final Thought
Patient safety takes priority over restoring the user interface. External inspection, power verification, controlled restarting, and repeatable functional testing provide a logical path without unnecessary disassembly. Clear CCR documentation supports safe escalation and efficient repair.
That is successful troubleshooting.