Geeetech

I'm reading 24v between the positive terminal of the power supply and the sd card slot's metal case. Is this normal?

I'm in the process of replacing my Makerbot Replicator 2's control board with the Geeetech MightyBoard Rev. G. I noticed that the sd card slot's metal casing seems to be connected to the negative power terminal. I discovered this by connecting a multimeter/voltmeter between the positive terminal of ...