Update = After completing troubleshooting, a DELL-Cares agent setup an exchange which resolved the issue.
There is no forum section for docks or other equipment  I have just bought a new W19TBS to replace a borrowed TB16. It emits a scratchy/sparking sound whenever more than idle power is drawn by the connected laptop. It sounds like an old worn out magnetic hard drive seeking or electrical arcing buzz. If sat idle then it only makes an occasional sub 1 second zzzz sound, but whenever I do anything to increase CPU usage (eg run any application, navigate between webpages) it makes the noise for as long as the load is above idle. If I connect the laptop's own power supply (and unplug/replug the dock to cause it to renegotiate the power contract with USB C port) then the noise does not occur. This confirms that it's to do with the power draw. It looks like it's the same issue reported here: [URL] which appears to have been resolved as normal, but in a quiet room when sitting over a meter from the dock this noise is impossible to ignore and makes me cringe in anticipation of smoke/fire erupting from the dock. The TB16 is totally silent. Do all W19TBS docks have this issue or is it possible to get it replaced with one that doesn't? If it really is normal for the W19TBS I'll have to create some sort of sound proof housing for it under my desk -- at least the thunderbolt cable is longer than the TB16's!
W19TBS Electrical Scratchy/Hissing Noise