Explanation
One of the possible causes of the error message "No input source" is that the LCD projector is not receiving any signal from the connected device, such as a laptop1. This could be due to a loose or faulty cable or connector, or an incorrect input source selected on the projector2. Therefore, the first troubleshooting step that the technician should take is to check the physical cabling and make sure it is properly connected and secured12.

Explanation
If a user is unable to log in using the fingerprint reader on a company laptop after the motherboard was replaced, it could be due to an issue with the fingerprint software. The first step to fix the issue would be for the technician to reinstall the fingerprint software.

Explanation
Dynamic Host Configuration Protocol (DHCP) allows a networked device to always be assigned the same IP address based on the device's MAC address. DHCP can also assign other network configuration settings to devices automatically.

Explanation
If a technician is implementing a SOHO wireless solution with three access points and wants to avoid high latency, the technician should configure all devices with different channels. By configuring all devices with different channels, the technician can ensure that the wireless signals from each access point do not interfere with each other, which can cause high latency.

Explanation
Checking if the password and SSID are correct is the best step that the technician should take to resolve the issue of a user being unable to access the SOHO wireless network after replacing the gateway. The new gateway may have a different password and SSID than the old one, which would prevent the user from connecting to the wireless network. The technician should verify that the user has entered the correct password and SSID for the new gateway. Assessing the network cables for damage, disabling Bluetooth connections, or updating the firmware are not likely to solve the issue, as they are not related to the wireless network authentication