Hi,
I do have a link to some schematics for older 260 versions, as well as user manuals. The evolution to the newer versions was usually a different choice of batteries, and newer versions (after about version4) incorporated better circuit protections. Otherwise, if it is just the low current ranges that do not work, there should be a small bobbin of resistance wire that has burned out, which was a common failure in those.
http://bama.sbc.edu/simpson.htm
:I need schematic and data for above meters anybody can help me get,thank you.