Hi Tomas,
1) To rebuild the 2225B battery, you will need : 6 Sub Cs Ni-CADs or NiMh, one picofuse if the one in the pack is burned, strength.
Choosing Ni-CADs or NiMh is a matter of use and taste. You'll find reasonable, skilled people or even ayatollahs defending opposite views. See posts and flames about this elsewhere in this Forum.
1a) Open the thing : The case is not welded but snapped, just exert enough pressure with the largest flat screw driver as the innards are tuck with very strong double-sided tape.
NOTE polarity of the existing cells connection alongwith picofuse position!!!
1b) Desolder and dispose/recycle the old cells SAVING the picofuse you'll find between them.
1c) Assemble the new cells in series with the picofuse (picofuse position & polarity not strategic)
1d) Resolder to the pack circuit, respecting polarity, and insert in pack with very strong double-sided tape ON THE BOTTOM.
1e) If you really wish to recreate new problems and stress when opening again, apply same tape to secure the cover.... Otherwise refrain...
1f) Charge outside the Thinkjet, monitoring carefully smells, gassing, funny noise....
1g) Test voltage at 7,2V loaded and use.
2) You may purchase the Thinkjet batteries...just anywhere on the Web or real world. They are still for sale new.
I think they come in black, blue or red.
Being in Europe, I did not test US Webstores but you may try Here (US) or here
Hp is now just a major paper and ink cartridge "manufacturer"/reseller and they incidentally distribute computers and printers to fit on their cartridges.
Cheers from France!
Etienne
Edited: 22 Oct 2005, 4:25 p.m.