| Problem | Possible Cause | Solution | |---------|----------------|----------| | Charger won’t turn on | No mains power / Internal fuse tripped | Check outlet / Unplug for 15 min | | Error LED flashing | Reverse polarity | Swap red/black clamps | | Charging LED stays red forever | Battery sulfated or too large | Try Repair Mode or replace battery | | Full LED comes on immediately | Battery already charged OR faulty connection | Check terminal contact | | Buzzing sound from unit | Normal transformer vibration | No action unless excessive | | Yellow LED stays on >6 hours | Heavily sulfated battery | Leave overnight; replace if no change |

: Connect the Red (+) crocodile clip to the positive terminal of the battery.