238-100E

Power Down Control Safely

Perform a controlled shutdown of the TNC control. Switch main power OFF and wait at least 5 minutes for all capacitors to discharge before opening the control cabinet.

Always follow LOTO procedures. Verify zero voltage with multimeter before touching components.

Remove and Inspect UVR Module

Carefully extract the UVR module from slot position %2. Inspect the module label for correct type designation and part number. Check for any burn marks, damaged components, or physical damage to the PCB.

Document the original slot position and orientation. Take photos of module labels showing serial numbers and firmware versions for replacement reference.

Clean and Reseat Module

Use electronic contact cleaner on the edge connector pins of the UVR module. Clean the backplane slot contacts with compressed air and contact cleaner. Firmly reseat the module ensuring it clicks fully into position.

Apply light dielectric grease to edge connectors if operating in humid environments, but avoid over-application which can attract debris.

Test with Module Swap

If multiple UVR modules are present, swap UVR%2 with UVR%1 positions and power up. If the alarm moves to the other module position, the UVR module is defective. If alarm stays with position %2, the backplane slot is faulty.

Before swapping, enter MOD 56 (system configuration) and document current settings to verify proper detection after module exchange.

Replace Defective Module

Order exact replacement UVR module using the part number from the defective unit. Install new module and verify detection in MOD function diagnostic screen showing correct module type and firmware version.

Using incorrect UVR module types can cause system instability or damage. Always verify part number compatibility with Heidenhain technical documentation for your specific control model.

Access Control Cabinet Safely

Power down and lockout the control. Open the cabinet and locate the backplane where UVR modules are mounted. Identify connectors X101 and X102 associated with the UVR%2 position.

Wait minimum 5 minutes after power-off before touching internal components. Verify zero voltage at backplane with multimeter.

Inspect Backplane Connectors

Examine X101/X102 connectors for proper engagement, damaged pins, or signs of arcing. Check for loose mounting screws on the backplane itself that could cause intermittent contact.

Use a flashlight and magnifying glass to inspect for hairline cracks in solder joints on the backplane, especially if the machine has experienced heavy vibration or thermal stress.

Verify Connector Integrity

Disconnect and reconnect X101/X102 connectors, ensuring positive locking engagement. Measure continuity through critical detection signal pins per the schematic diagram for your specific control variant.

Typical hardware detection signals use pins 1, 2, and specific ground references. Consult the electrical schematic in your machine documentation for exact pin assignments.

Check Backplane Slot Contacts

With module removed, inspect the backplane edge connector receptacle for bent, corroded, or broken contact fingers. Use contact cleaner and carefully straighten any bent contacts with precision tools.

Excessive force when straightening contacts can break them completely. Work slowly and verify alignment before reinserting module.

Test and Verify Detection

Reinstall UVR module and power up. Enter MOD function and navigate to system status display to verify UVR%2 appears with correct identification. Monitor for alarm recurrence during thermal cycling.

Leave the control cabinet open during initial power-up tests to observe module status LEDs. Proper detection typically shows steady green LED on the UVR module.