Danfoss FC302 AL-107 Fault Code — What It Means
The code AL-107 does not exist in Danfoss FC302 documentation. The FC302 series uses numeric alarms (Alarm 13, Alarm 38) or alphanumeric codes like AL 15 or AL 17, but no alarm 107 or AL-107 appears in official fault lists. If you saw this code on the display, it is likely a misread or a typo.
The closest valid alarm is AL 15 (Hardware Mismatch), which indicates the drive has detected a non-compatible or improperly installed option card such as a brake control card, serial communication module, or encoder interface. The drive does not recognize the card, or the card is seated incorrectly, damaged, or not certified for the FC302 model. This is a logic compatibility fault, not a power or sensor issue.
Before You Replace Anything
Technicians sometimes replace the logic board when the actual problem is a dirty or bent connector on the option card. Always inspect, clean, and reseat the card before ordering a new control PCB.
Common Causes
- Option card not fully seated (~40%) The card is not engaged completely in the slot, so the drive cannot read its ID or communicate with it.
- Wrong or incompatible option card model (~30%) The card was designed for a different drive series (FC202, FC101) or firmware version and is not certified for the FC302.
- Damaged option card PCB or connector (~20%) Physical damage, corrosion, or bent pins prevent proper contact between the card and the drive backplane.
- Outdated drive firmware mis-flagging hardware (~10%) The drive firmware incorrectly reports a hardware mismatch even when the card is compatible.
Quick Diagnosis
Answer these to narrow it down fast.
Does the AL 15 alarm appear immediately after installing an option card?
No: The card may have failed over time or the drive firmware is outdated. Try updating firmware or replacing the card.
Does the alarm clear when you remove the option card and restart the drive?
No: The logic board or control PCB may be damaged. Call a qualified VFD technician to test internal communication.
Can you see physical damage (bent pins, corrosion, cracks) on the option card connector?
No: Verify the card part number matches your FC302 model. If correct, update drive firmware or replace the logic board.
Step-by-Step Fix
- Power off the drive and disconnect AC mains at the supply breaker or disconnect switch.
- Remove the front cover of the FC302 and locate the option card slot on the control PCB.
- Pull the option card straight out of the slot and inspect it for bent pins, corrosion, cracks, or burn marks.
- Check the part number on the card label against the Danfoss FC302 compatibility list in the installation manual.
- Clean the card edge connector with electronics contact cleaner and let it dry completely.
- Reseat the card by aligning it with the slot guides and pressing firmly until it clicks into place.
- Restore power and reset the drive by cycling the control power or pressing the reset button on the keypad.
- Monitor the display for 30 seconds. If AL 15 clears, the repair is complete. If it persists, remove the card and run the drive without it to confirm the card is faulty, then order a replacement.
Parts Often Needed
| Part | Notes |
|---|---|
| Danfoss FC302 option card (brake control, encoder, communication module) | Amazon | Verify the exact part number from your drive nameplate and the compatibility list in the manual. |
| FC302 logic board (control PCB) | Amazon | Only needed if the drive firmware is mis-flagged or internal communication fails. Available from Danfoss or Wake Industrial. |
When to Call a Pro
Call a qualified VFD technician if you have updated firmware, reseated or replaced the option card, and the AL 15 alarm still appears. The issue may be a failed logic board, damaged internal communication bus, or a non-standard drive configuration requiring factory service. High-voltage components inside the drive remain energized for several minutes after shutdown, so only trained personnel should open the enclosure or test internal circuits.
Rough cost: A pro service call runs about $150-400.