Both HX-20 and PX-8 came with some variation of the HOOAA? Adapter (HOOAAG for 220V, HOOAAU-A for 240V, ...) Not sure about the PX-4, which has smaller cells, but charges ok with the adapter mentioned above. You can replace the old C-type NiCd cells with modern NiMh penlights. The capacity is similar and so is charging (using the primitive way Epson implemented it). And these are considerable cheaper. I did make a small page containing the information I have on the PF-10: http://www.xs4all.nl/~fjkraan/comp/px8/pf10/. Important to know is that the unit is not designed to be used from the mains adapter. This is only for charging. Charging and operation should not be done at the same time. Fred Jan