On the OPTOMA HD700X projector, the Source Lock function controls the detection of connection ports. When this function is enabled (On), the projector only searches for the currently defined port and ignores other inputs, which can give the impression that a source is blocked when the device is turned off.
To unlock the source and restore automatic detection, follow these steps: Turn on the projector and press the Menu button on the remote control or control panel. Use the directional keys to navigate to Options and press Enter. Scroll down to Source Lock and select it.
In the Source Lock menu, you will see two options: On (locks the projector to the currently connected port) and Off (enables automatic detection on all ports). Set this option to Off to allow the projector to automatically search for a source on all ports (VGA, HDMI, Composite, etc.) when it starts up. Confirm with Enter and exit the menu.
If the problem persists after this procedure, check that all signal cables are properly connected and in good condition. You can also try a complete restart of the projector: turn it off by pressing Power twice, wait for the cooling cycle (about 10 to 15 seconds), unplug the power cord for 30 seconds, then plug it back in and turn the device on. This reset may resolve source detection issues.
