[Ancient Geek]

Thought you would have. However, I still say you need to check the power supply with a scope while operating. From what I can see, there is an on-board regulator with a filter cap next to it, which you should also check. Also, I gather that not only is the unregulated supply routed through the power switch, but so is the regulated supply, and this has been known to cause problems. The key scanner will be driving fairly long lines and I reckon that good supply and decoupling will be crucial.