The Druck DPI 601 is a handheld digital pressure indicator and calibrator that uses an internal micro‑transducer to display pneumatic pressures and can generate 0–5 V or 4–20 mA signals for external transmitters. Common failure modes include loss of display, erratic or drifted readings, incorrect output voltage/current, and power supply (battery) depletion; these are typically caused by internal transducer wear, PCB component fatigue, or connector corrosion. First‑check diagnostics: verify the unit’s battery level and power indicator, measure input pressure signal with a known reference to confirm sensor accuracy, and test the 0–5 V/4–20 mA output against a calibrated source; inspect for visible damage or loose connections before proceeding to internal component replacement.[oss-gpt-20b]