As the title says, my 5k+ was dead out of the box. I get a red power light but nothing else. PiTool says 10600, display port not connected. I have followed every guide and trick posted by people with similar issues, but there is no change.
EDIT: This turned out to be a software issue - the version of PiTool in the setup guide (and the one recommended in the large thread about this issue) seems to not be compatible with my setup.
Allan connected via TeamViewer, downloaded some other software directly by a URL, and my 5k+ immediately began working correctly.