Slightly OT - looking for power adapter info for Palm III GPS

[Ethan Dicks]

The Palm isn't quite 10 years old yet, but at least this is cool
hand-held tech...

I have this Rand McNally Navman/Streetfinder GPS that wraps around a
Palm III, and I have lost track of which wall wart charges it up. 
There is, of course, no power information molded into the case, and as
of yet, I have been unable to google any specs.  Does anyone on the
list happen to have one of these, or even just know what the input
voltage is?  I suspect it might be 12V, so that a simple lead can
charge it in the car, but even an examination of the innards hasn't
been revealing.  I did run across a variable voltage car adapter with
the right tip set to 9V.  Since I don't have many devices with that
particular tip (it's the smallest female coax connector in the
standard Radio Shack kit), I have reason to suspect that I may have
rigged this up some years ago, but I have no direct proof.

I realize I should have scrawled the power info on the back with a
Sharpie, something I will now do, once I put this thing back in
service.

Thanks for any tips,

-ethan