Hello, José;
About the HP71B, I asked a few questions to Doc. Mike Meyer a couple of days ago and I was told that the same AC adapter used by the topcats (HP9x), HPIL printer and tape driver, HP9114B and HP82143A (HP41 printer) can be used with it. I tested and it works fine.
I am using four AAA NiCads with mine and I was also told by Doc. Mike Meyer that the HP71B cannot charge batteries. The AC adapter works the same way that the AC adapter for the HP82240A/B: it feeds part of the power, but cannot charge batteries. Kind of "power support".
If you have the MoHPC CD pack, have a look at CD #2 (if I am not wrong) and you will find the book "Controlling the Word with the HPIL". There are many good information there. I read a few parts of it briefly, because I'm still learning hwo to deal with the HP7.
One thing I did so far was to connect the HP41 to the HP71B and execute ID in the HP41 (if I am not wrong, ID is an Extended I/O function, not a standard HPIL funciton; you should check, please) and I could read:
[HP71 ]
in the HP41 ALPHA register. They talked to each other!
As I'm getting acquainted to the HP71 I'm asking more questions, too.
Hope this helps for now,
Best regards.
Luiz C. Vieira