How to Troubleshoot a CUR on a V12 MRD-M605

Faulty wiring is a common cause for over-current problems.

Adding an amplifier and subwoofer to your car’s audio system will definitely enhance your audio experience, but a more complex sound system is more prone to problems. One common problem in such systems is over-current, which consists of excessive power being drawn from the amplifier’s outputs, triggering the amplifier’s over-current protection. In the Alpine MRD-M605 amplifier, this problem is indicated by the appearance of the error message “CUR” on the amplifier’s display. There are multiple factors that can lead to an over-current problem and in most cases the problem can be easily repaired.

Instructions

1. Unplug the pair of RCA cables and speaker wires from the amplifier.

2. Turn on the system and inspect whether the “CUR” message is still displayed. If the message is still displayed with all the cables unplugged, the problem is inside your amplifier. Send your amplifier in for warranty service or to an authorized service center for further inspection and repairs. If the message disappears, proceed to the next steps to identify and fix your problem.

3. Plug the pair of RCA cables into the amplifier. If the “CUR” error appears again, the problem is most likely with the RCA shielding. If there is no error, proceed to the next step.

4. Connect the speaker wires to the amplifier. If the over-current protection is triggered and the error appears, the problem is with the speakers or speaker cables. Disconnect the speaker wires from the speaker, leaving them connected to the amplifier and power on the system. If the problem is still there, the wires are faulty or have grounding contact. If the problem only appears when you reconnect your speakers, the speakers are faulty and need replacement.

Tips & Warnings

• Buy only speakers with the specifications matching the amplifier. Different power and impedance can lead to problems.

• Do not attempt to open and fix the amplifier yourself unless you’re qualified to do so, otherwise you will automatically void its warranty and most likely aggravate the problem.

References

• Crutchfield: Alpine MRD-M605 Owner’s Manual
• Basic Car Audio Electronics: Amp in Protect Mode – Troubleshooting

Resources

• EE Times: Over Current Protection in Audio Amplifiers
• Basic Car Audio Electronics: Basic Amplifier Repair
• Basic Car Audio Electronics: Temporary RCA Shield Repair