This may seem really crazy but I learned something from a pretty wise fellow synth-head when I was putting together my set-up three years ago, post-military.
He advised me to get a set of Sharpie Paint Pens or equivalent that have tip to write in a discerning manner, on each power supply name of instrument it belongs to both on the top of the PS and on side for this possible error aforementioned, and it comes in really handy in cable management when having to ultimately sort say a ground loop or issues that do come-up.
I know this sounds as basic as the wise use of power conditioners, especially when relying on House Power when playing out…but this has served me well and have even bought used synths where durable duct tape was still on power supply with label on tape of instrument.
Hope this helps even one person and hope your A4 recovers.

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