The Fieldpiece HS26 is a rugged “stick” digital multimeter designed for HVAC/R and industrial use, featuring AC/DC voltage, resistance, continuity, diode, micro‑amp DC, and capacitance measurements with interchangeable heads. Common failure modes on this model include display backlight or LCD failure, button drift, battery contact corrosion, and input head connector wear that can cause spurious readings or loss of range selection. First‑check diagnostics: verify the 9V/AA battery voltage and clean contacts; inspect the front panel buttons for mechanical binding or debris; confirm continuity on the internal power supply traces and check the display module’s solder joints for cold connections.[oss-gpt-20b]