AC Charger for HP-21

[smp]

OK, so I've (now) done some looking around, and it appears that the HP-82026A charger would be the one that I want.

As far as the battery pack goes, I would appreciate hearing what folks think about the advisability of modding the battery pack and installing two AA Alkaline batteries. If anyone can point me to a site that shows a how-to for this, I would appreciate that, as well.

Thanks,
smp