USB powered HP41

[Neve]

Hi all,

I'm kinda new here. So excuse me if I ask questions that where asked of discussed many times around.
After some research, I camo across several posts On this subject. Like this one for example:

http://www.hpmuseum.org/cgi-sys/cgiwrap/...722#183722

I thought of using an iPhone wall USB plug as the power supply. It delivers 5V/1A

Several issues come to mind, though:
1- Would the 5V provided by the USB suffice to properly power the card reader?
2- Shouldn't the battery pack be removed before plugging in the USB power supply? If not, it will probably add another 5V or 6V depending on the current battery charge! (I haven't seen the schematics yet). Could the circuit handle it?
3- Does anyone know where the + and Grnd are on a Fullnut circuit board if I decided not to use a module/slot? That would save me some time if I decide to go that route.

I have an idea that I will gladly share if I can make this work.

Thank you all.