My USB-C dock charges the laptop but shows no picture—what should I check before buying more?
TechnologyThe shop assistant pointed at the charging light and said, ‘The port works. You probably need a better cable.’ The cable was another $29, on top of my $68 dock.
The dock advertises DisplayPort Alternate Mode. My laptop charges through it, but the monitor stays blank. The monitor works through the laptop's separate HDMI socket. I wanted one plug for the whole desk; I have not checked what my exact laptop model supports through USB-C.
Microsoft's troubleshooting says the equipment and cable need to support the appropriate display mode. That makes me doubt the charging light settles this. [Microsoft's USB-C guidance](https://support.microsoft.com/en-us/windows/hardware/usb/fix-usb-c-problems-in-windows).
The shop will let me bring everything back tomorrow. What test should I ask for before buying another cable? I would happily pay to solve the problem, once someone can show me what the problem is.