231-8044

Power down and inspect fan assembly

Shut down the TNC system properly via MOD function, disconnect power, and visually inspect the CC controller fan for debris, cable damage, or physical obstructions.

Ensure complete power isolation before opening controller enclosure

Test fan rotation manually

Gently rotate fan blades by hand to check for bearing roughness, grinding, or excessive resistance that indicates mechanical failure.

Smooth bearings should allow easy, quiet rotation with slight resistance

Clean and clear obstructions

Remove dust, debris, or cable interference using compressed air and ensure fan housing ventilation paths are clear.

Use anti-static compressed air and avoid spinning fan faster than normal operation

Replace fan if mechanically damaged

If bearings are rough or fan blades damaged, replace with HEIDENHAIN-approved fan assembly matching CC controller specifications.

Use only specified replacement parts to maintain proper airflow and electrical compatibility

Check fan connector integrity

Inspect fan power connector on CC controller for loose connections, corrosion, or damaged pins that could cause voltage drop.

Look for discoloration around connector pins indicating overheating

Measure fan supply voltage

Using multimeter, verify fan receives proper voltage (typically 12V or 24V) at connector while system is powered and compare to CC controller specifications.

Measure voltage with system powered - use proper electrical safety procedures

Test internal power supply rails

Check CC controller internal power supply voltages using TNC diagnostic functions or direct measurement to identify power supply degradation.

Access power supply diagnostics through TNC service menus if available on your controller version

Replace power supply module if faulty

If voltage measurements show deviation from specifications, replace the CC controller power supply module or entire controller unit as required.

Power supply replacement requires proper ESD precautions and HEIDENHAIN service procedures

Verify actual fan operation

Visually confirm fan is rotating at normal speed while alarm is active to distinguish between actual speed problems and sensor failures.

Compare fan speed to similar functioning systems or use non-contact tachometer for verification

Check sensor signal integrity

Inspect fan speed sensor wiring and connections for damage, and test sensor output signal using oscilloscope or multimeter if accessible.

Sensor circuits may be integrated into fan assembly and not user-serviceable

Reset controller diagnostics

Clear alarm using TNC alarm reset function and monitor for immediate recurrence to help isolate intermittent sensor issues.

Document alarm frequency and conditions to identify patterns in sensor malfunction

Replace fan assembly with integrated sensor

If sensor is confirmed faulty and integrated with fan, replace complete fan assembly with HEIDENHAIN-specified part including speed monitoring.

Many CC controller fans have integrated speed sensors that cannot be serviced separately

Check ambient temperature conditions

Measure ambient temperature around CC controller and verify it's within HEIDENHAIN specifications (typically 0-45°C operating range).

Check for heat sources like servo drives or other equipment affecting local temperature

Inspect ventilation pathways

Verify all controller enclosure ventilation openings, filters, and air circulation paths are clear and unobstructed.

Blocked ventilation can cause rapid controller overheating and component damage

Monitor internal controller temperature

Use TNC diagnostic displays to check internal temperature readings and compare to normal operating ranges for your system.

Access temperature monitoring through TNC service diagnostics or MOD function temperature displays

Improve cooling system capacity

Add supplemental cooling, improve enclosure ventilation, or relocate heat sources to reduce thermal load on CC controller.

Consider upgrading to higher capacity cooling fans if thermal load consistently exceeds original design

Document alarm pattern and frequency

Record when alarm occurs, system conditions, and frequency to identify patterns indicating controller hardware issues versus external causes.

Keep detailed log including ambient conditions, system load, and any recent changes

Perform CC controller diagnostics

Run comprehensive TNC system diagnostics and hardware tests to identify internal controller faults or degraded components.

Advanced diagnostics may require HEIDENHAIN service tools or technician access

Check controller age and service history

Review CC controller installation date, previous service records, and compare to expected service life for proactive replacement planning.

Controllers over 10-15 years old may require more frequent monitoring or preventive replacement

Plan controller replacement

If hardware degradation is confirmed, schedule CC controller replacement with compatible HEIDENHAIN unit and proper data backup procedures.

Ensure proper TNC parameter backup and restoration procedures before controller replacement