Honestly I'd check the buttons. When stuff gets spilled on a machine, it almost always gets into the buttons. It's like magic. However, if you're getting voltages that are too low, that's a power board issue, no? Are you getting correct voltages at the plug?

Also, is your ground connected from head to body? If there's voltage on your ground, it'd explain why the readings are off.

Yeah. It's one of those things. Always start with the basics and then move forward.