The JC150 is a single‑axis industrial joystick controller that uses a long‑life conductive plastic potentiometer track and spring‑to‑center or friction‑hold action, sealed to IP65 for harsh environments. Common failure modes include worn potentiometer tracks causing erratic position signals, end‑switch or center‑switch failures, connector corrosion on the AMP 040 interface, and power supply voltage drops that trigger the controller’s fault logic. First‑check diagnostics: verify 24 V DC input and correct polarity; visually inspect the lever, potentiometer track, and switches for wear or damage; test the output voltage sweep across the joystick range with a multimeter or oscilloscope; and examine connector pins for corrosion or loose contacts.[oss-gpt-20b]