Which EGT do I believe??

[Cattletrkr]

Here's another question for whomever can answer. What should my Autometer EGT gauge read when there's no power at all to it. I've got it on a switch rather than plugged into an ignition line somewhere. When I turn the switch off it flops around quickly and points straight down, no marks down there. I seem to remember it laying somewhere around 30-40* when it was new but I could be making that up.

 

[Mundgyver]

I see that with my Autometer also. I think what you are seeing is the electronics of the interface box discharging their current to a state of electrical 0, at least that is my guess.