Taylor model 85A s/n 404997 with Instruction manual
This 90 range multimeter which has a 40 microamp movement is housed in an wooden case. The instruction manual indicates that a total of 90 ranges are available. This seems very impressive but as far as I can make out from the tables in the booklet only 55 are available without the need for additional adapters or power supplies.
This instrument was very grubby when I received it and the pointer touched the dial at the left hand end of the scale. Removing the four screws enables the front of the meter to be removed. I was then able to straighten the pointer and bend it slightly to stop it catching the dial.
The movement now worked and the meter appeared to give correct readings on the AC and DC voltage scales. The resistance ranges worked, but the RX100 range gave problems, there seemed to be a leakage across one of the switch wafers which was eventually resolved with switch cleaner and a small brush.
Batteries This model used a rectangular 1.5 volt cell and a grid bias battery with brass sockets which were both housed in a compartment on the underside of the instrument. I have modified the connections to utilise a 9 volt PP3 battery.
How old is it? I guess this was made in 1946/7, The variable resistor used for zeroing the ohm ranges is an Air Ministry item and the capacitor is marked 10/6 which is possibly the date code for week 10 1946.
What is it worth? Mine cost me £ 5.00, so not much!
You can download the instruction manual which is a large file (3.3 MB) here I have also included a summary of the ranges and switch positions to fit inside the lid made by a previous owner.
Taylor Electrical Instruments Ltd of Slough was incorporated in January 1939 and was taken over by AVO Ltd. in 1958. Soon after in 1959 Metal Industries Ltd acquired Avo Ltd, including its subsidiary Taylor Electrical Instruments Ltd and in 1967 Thorn Electrical Industries took over Metal Industries.