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Could be as simple as moisture in the plug jack of the control. That should be a phone type plug, if your not afraid of electrical...Turn the spa off, open the panel, locate the cord comming from the control and unplug it, blow it off and plug it back in. Turn the spa on and see what happens.
With today's technology, why didn't he take out his cell phone and call Artic Technical Service right from the spa? Save time, money, second trip, puts the spa back in service and we are talking about what he dosen't know. Imore?