Curtis Instruments 17400700 is a joystick controller used in industrial control panels, featuring programmable function keys and an integrated emergency‑stop (E‑Stop) circuit. Common failure modes for this class of devices include degraded or broken potentiometers, burnt‑out I/O relays, and failure of the E‑Stop contactor due to mechanical wear or electrical overstress. First‑check diagnostics should verify that the unit receives its rated input voltage and that all power rails are within tolerance; inspect the joystick shaft and potentiometer for smooth operation and check the E‑Stop contacts for continuity and proper engagement. Finally, review any diagnostic LEDs or error codes displayed on the panel to isolate a specific fault line before proceeding with component replacement.[oss-gpt-20b]