130-0130

Power down the control completely

Perform a controlled shutdown via the operating system, then disconnect mains power. Wait minimum 2 minutes for capacitors to discharge before opening the control cabinet.

Ensure main power disconnect is locked out. High voltage present inside control cabinet even after shutdown.

Inspect and reseat internal modules

Open the TNC control cabinet and locate the CC module and PLC cards on the backplane. Carefully remove each module, inspect the gold contact pins for oxidation or damage, clean with contact cleaner if needed, then firmly reseat ensuring proper engagement with backplane connectors.

CC modules often have a green status LED - note if it was illuminated before removal. Lack of LED indicates module power or communication failure.

Check backplane ribbon cables

Inspect all ribbon cable connections between modules and the main board. Look for crushed cables, bent pins, or loose IDC connectors. Reseat all internal communication cables with firm, even pressure.

Ribbon cables should have strain relief and should not be kinked. A single broken conductor can cause intermittent bus errors.

Power up and verify in diagnostics

Restore power and boot the control. Immediately access MOD function > System Configuration > Component Status to verify all modules are recognized. Check for green status indicators next to CC and PLC module entries.

If a module shows red status or 'Not Found', that specific component is the fault source and requires replacement.

Access software version information

Navigate to MOD function > Information > Version Display. Record the NC Software version, PLC Software version, and CC Firmware version. Compare these against each other - they should have compatible build numbers per Heidenhain version matrix.

For TNC 640 controls, NC and CC versions should match in the first two digits (e.g., NC 340.590-xx with CC 340.xxx-xx).

Check update log for errors

In MOD function > System Configuration > Diagnostics > System Log, filter for entries from the last software update date. Look for incomplete update processes, checksum errors, or module flash failures.

Search for keywords 'FLASH', 'UPDATE', or 'CHECKSUM' in the log file to quickly identify update-related issues.

Re-flash peripheral module firmware

Access MOD function > Software Update > Update Peripheral Modules. Select the CC module and PLC software components individually and execute a complete reflash cycle using the correct software package from Heidenhain matching your NC version.

Never interrupt power during firmware flash process. Ensure UPS or stable mains power. Interruption will brick the module requiring factory return.

Perform full system reboot and verification

After successful firmware update, perform a complete power cycle (not just soft reboot). Verify alarm clears and run Test Run mode with a simple program to confirm full communication restoration between NC and peripherals.

After reflashing, initial boot may take 2-3 minutes longer as modules perform internal checksums and synchronization.

Monitor supply voltages under load

Using a true RMS digital multimeter, measure DC voltages at the control power supply test points while control is fully operational. Check +5VDC (should be 5.0V ±0.25V) and +24VDC (should be 24.0V ±1.2V). Monitor for at least 5 minutes to catch fluctuations.

Measurements must be taken with control powered and operating. Use insulated test probes and avoid contact with adjacent terminals.