I've got several old Metz hammerhead flashes, a couple of CL-45 and a couple of CT-45. The CL-45's work just absolutely fabulous for providing bounce--and fill--lighting simultaneously. I was thinking of picking up a used Metz 70 MZ-5, but have read that their power supply can be a PITA, namely trying to get replacement batteries if the old ones no longer hold up charge. I'm not even sure if Metz makes replacement batteries for these anymore. So what are the alternatives? Can these be modified to take AA alkaline batteries? Can they be modified to take third-party replacement batteries? I did read where someone did that, but it was quite tricky.