Thanks this is all great information, I'm working the same issue with a unit I recently acquired.

Just a minor detail, I found, on the unit I have, I could enter the "diagnostic menu" by pressing and holding the "Time" icon, just to the right of the battery icon, for 30 seconds. I got there accidentally when I missed the battery icon. I know these units are all probably a little different, so it's hard to predict every scenario.

Thanks again,