Precision Apparatus model 856-G Multimeter

Precision Apparatus Company model 856G Multimeter first produced in 1943 it has an open circuit meter movement which I have now replaced with a similar sized meter from a Simpson model 260 multimeter which has a 2000 ohms/volt meter movement, I scanned the scale from the faulty meter and stuck it to the scale plate of the replacement.  The variable resistor in the meter was not making good connection and I could not reliably adjust the meter plus swamp value to 2000 ohms so selected a close tolerance resistor to bring it to 1991 ohms which I thought good enough. The meter now worked but was reading significantly low.  working but inaccurate USA 1943

This was given to me by Susan Harper. It was one of many instruments which belonged to her late father. His working background of 50 years started at Mullards, then on to TMC in Cray Valley, Kent, which then, in turn, went onto become PYE/TMC. to finally be taken over by Phillips. Test equipment telecommunications being very much his field. He continued to 'tinker' about in his office during his retirement.

When I looked inside it was obvious that the meter had been removed and put back many years ago, there was no 22.5 volt battery but the vintage single cell shown here still provided about one volt. The meter movement is stamped 1447 but the other components are marked 1443 which tends to indicate that the original meter movement had been replaced, possibly from a later production model. Interestingly there were two brackets, two knobs and a set of sockets, from a similar instrument which presumably had been taken apart.