Fieldpiece HS35 is an auto‑ranging stick multimeter designed for HVAC/R field service, featuring a magnetic hanger, detachable silicone test leads, alligator clip probes, and built‑in safety functions such as CAT‑III input protection and a PTC heater. Common failure points include the internal microcontroller or display backlight, the battery/charging circuit, and the probe connector contacts; these often manifest as erratic readings, no power, or a dead screen. First‑check diagnostics: verify the unit’s power supply (battery voltage and charging port), inspect alligator clip and test lead connections for corrosion or damage, and confirm that the display and backlight LEDs are functioning before proceeding to internal component testing.[oss-gpt-20b]