[sdiy] Intermittent ground hum (?) on spirit mixer (psu?)

[Julian]

Hi there,

My mixer is irritating sometimes.  Real occasionally, if things have been moved about around its external psu, it makes this god
awful buzzing noise, like a ground hum or something.  Moving the psu again seems to solve this, but its one of those real
intermittent faults that im not sure how to investigate.

Im assuming that probably something is amiss in the wire between the plug and the transformer, or transformer and mixer.

I havent even taken a look inside yet, but i thought id just ask for suggestions here first, in case anyone had any clear ideas?

The mixer is a spirit folio f1, with a uk psu (if that makes any difference).

Comments welcome?

Cheers, Julian