New-to-me HP-71B

[rprosperi]

71B machines as far back as 2404A... are all ROM version 1BBBB. The only confirmed 1AAAA unit reported here (since I started collecting info) is from 2401A, though I believe another unit from the same week was v1BBBB, so this is likely the week the change took place.

I'll also note that a 2405A machine has been reported to have v1AAAA. I own one also from 2405A, 27 units "younger" and it has 1BBBB, so I believe this 1AAAA unit is a frankencalc of some kind.

Further, 0AAAA units have been reported as well, though clearly pre-production/prototype machines.

Congrats on having a 71B again. Still the best machine of them all.