The Fluke T5‑1000 Yellow is a handheld voltage, continuity and current tester with an OpenJaw design that can measure up to 1 kV AC/DC and 100 A. Common failure points for this model include dead or low battery causing false zero readings, internal fuse blow from overcurrent on the probes, probe connector corrosion leading to intermittent contact, display backlight or LCD failure, and calibration drift after prolonged use. Initial diagnostic steps: verify the 9‑V battery voltage with a spare; inspect and clean the probe connectors for oxidation; check the internal fuse (if accessible) and replace if blown; and confirm that the unit’s auto‑range function is selecting correctly by testing known reference voltages.[oss-gpt-20b]