The orange light means that the hub cannot keep its supply voltage up. There’s a step-up converter that makes 5V out of the battery voltage, the orange light is on if the 5V cannot be reached. This can be due to several reasons:
- Batteries are empty, battery connectors are dirty, connector between battery case and hub top is dirty or damaged. Use Kontakt 40 Spray from KontaktChemie to clean all contacts (don’t spray into the box, take a piece of cardboard, soak it with the spray and rub the contacts with it).
- The hub is overloaded – the motor is stalled, the cable is broken and has a short, the socket at the hub has damaged contacts and causes shorts. Check, clean, replace.
- The power supply circuit inside the hub is damaged. This is a known issue showing up on older hubs. There was no consensus what really happens, I have not had a hub like that yet. Possible problems may be: cold or cracked solder joint, dried-up filter capacitor, crack in the PCB. LEGO was replacing hubs with this issue, I don’t know if this is still the case.