The Amprobe DM‑II PRO Data Logger/Recorder is a three‑phase power quality recorder that measures voltage, current, harmonics, energy, and power factor for diagnostic and compliance purposes. Common failures on this model include firmware corruption or data storage errors due to SD card wear, overheating of the internal temperature sensor causing inaccurate readings, and loose or corroded input contacts leading to intermittent signal loss. Initial checks should verify that the unit’s 12 V/5 A power supply is delivering correct voltage, inspect all phase input connectors for secure contact and insulation integrity, and confirm that the SD card is properly seated and formatted; if errors persist, review the internal error log via the LCD menu for specific fault codes.[oss-gpt-20b]