Why Optoma ZH39 Projector Remote Is Ineffective?

IR remote has its effective range. When your Optoma ZH39 Projector remote is ineffective, try follow the steps below to troubleshoot.

Infra-Red (IR) remote control sensor is located on the top and front sides of the projector. Ensure to hold the remote control at an angle within 60 degrees perpendicular to the projector’s IR remote control sensor to function correctly. The distance between the remote control and the sensor should not be longer than 12 meters (39.4 feet).

Make sure that there are no obstacles between the remote control and the IR sensor on the projector that might obstruct the infra-red beam.
Make sure the IR transmitter of the remote control is not being shined by sunlight or fluorescent lamps directly.
Please keep the remote controller away from fluorescent lamps for over 2 m or the remote controller might become malfunction.
If the remote control is close to Inverter-Type fluorescent lamps, it might become ineffective from time to time.
If the remote control and the projector are within a very short distance, the remote control might become ineffective.
When you aim at the screen, the effective distance is less than 5 m from the remote control to the screen and reflecting the IR beams back to the projector. However, the effective range might change according to screens.