How to troubleshoot no video output or abnormal images after installing a video optical multiplexer?

After a video optical multiplexer is installed with no video output, carry out troubleshooting in the following order: first confirm the receive/transmit relationship and wavelength matching of the optical ports at the transmitting end and the receiving end, and that the devices at both ends are used as a pair; then use an optical power meter to verify whether the received optical power is within the normal range; then check the cleanliness and full insertion of the optical fiber patch cord end faces and the optical port connectors; and confirm that the power supply is normal, that the connectors at both ends of the video coaxial cable are crimped reliably, and that the wiring type of the data cable matches the opposite end. For routine maintenance, it is recommended to switch off the power before inserting or removing the optical port, to clean the optical fiber end faces regularly with a dedicated tool and re-measure the optical power, and to route the data cable and the video cable separately. If all of the above checks are normal but the image is still abnormal, it is recommended to contact the manufacturer's technical support together with the device alarms.