Knowledge Base

Problem

During dark-phase or nighttime experiments the observation chamber's white or bottom light cannot be fully extinguished, or it turns on unexpectedly mid-experiment, invalidating results.

Details

Symptoms: The white light activates during scheduled dark periods for some but not all experimental runs (e.g., 2 of 6 replicate experiments), or remains permanently on. The light appeared to work normally during daytime (light-phase) experiments, masking the fault. Prolonged testing (up to 6 days) confirmed the fix. Root cause: faulty electronics/control box inside the observation chamber.

Solution

1. Confirm the issue is not a trial control settings misconfiguration: review the dark/light schedule in EthoVision XT Trial Control and verify settings are identical across all replicates.
2. If settings are correct but the light still activates during the dark phase, the control/electronics box of the DanioVision observation chamber is faulty.
3. Contact Noldus support to arrange replacement of the electronics/control box (this is a hardware repair — do not attempt to open the electronics box yourself).
4. After the replacement, run a multi-day validation test (≥ 6 days recommended) using your standard dark-light protocol to confirm the fault does not recur before resuming live experiments.