Simpson model 260 Multimeter which has a 2000
ohms/volt meter movement is
housed in an bakelite case. I have no instruction manual. It is one of
many instruments collected by Bob Evans
which I have
been given by his daughter Alice Kirby
It was very grubby when I received it, would not work on any of the
ranges and the batteries which had been in place for many years had
corroded the fixings.
I discovered that the meter movement was functioning but after a
cursory investigation decided that the instrument was not worth
repairing so I decided just to keep the meter.
Batteries two 3 Volt batteries, (Burgess 422 or Eveready 750)
and one ("C" Size) 1� Volt battery. Two "AA" cells soldered
together had been used as replacements for the former.
How old is it? according to this page http://simpson260.com/260-1/simpson_260-1.htm
this appears to be one of the earliest model 260 multimeters and would
have been made in the early 1940's or even earlier.
Schematic diagram
Paul R Schmidt has redrawn the original Simpson schematic,
as it was hard to follow, had missing critical information, and about
eight significant errors. This is the link to the PDF on his webpage
https://www.serpentwebsite.com/Simpson_260-1_CAD_schematic.pdf
You can find other details about suitable battery replacements on
this page
https://www.serpentwebsite.com/fileshare.htm