Use a multimeter to ensure the thin signal wire is not broken along the cable length.
Dell's standard round barrel connectors (like the 7.4mm or 4.5mm sizes) distribute these wires as follows: Wire Color (Typical) Outer Barrel Negative / Ground Inner Barrel Wall Positive (+19.5V) Center Needle Pin Charger ID / Signal Blue (or Green) Why the Third Wire Matters Blue ID wire
3 Wire Dell Laptop Charger Wire Diagram Best 90%
Use a multimeter to ensure the thin signal wire is not broken along the cable length.
Dell's standard round barrel connectors (like the 7.4mm or 4.5mm sizes) distribute these wires as follows: Wire Color (Typical) Outer Barrel Negative / Ground Inner Barrel Wall Positive (+19.5V) Center Needle Pin Charger ID / Signal Blue (or Green) Why the Third Wire Matters Blue ID wire 3 Wire Dell Laptop Charger Wire Diagram