Hi all,

I bought a ton of surplus electronic gear (almost literally) and among
some of the cases of odd bits and whatnot I came across an AOR AR3000
"communications receiver" (I use quotes as it's nothing like any *proper*
CR I've ever encountered, but I guess that's my age prejudice). Anyway,
it has 3 pins on the back panel marked "12V DC in" but no polarity
indication. I'm guessing one of those pins is just for alignment to
ensure the plug goes in the right way around and the other two are pos
and neg. I can find no power lead for this radio. Is it possible to
determine which pins are which from carrying out some basic resistance
measurements between them? I really don't want to hook it up the wrong
way around.
BTW, the service manual I have downloaded off the net does not help at
all in this respect.

TIA.