This sorry looking instrument contains a Weston standard cell (1.01 volts) manufactured by Tinsley in 1961. Unfortunately the cell voltage is now only 43 millivolts! The other problem was that the taut wire of the galvanometer suspension was broken. I have soldered the finest wire I could find to enable it to more or less function.
Here are the large 1.5 volt cells which power the two parts of the circuit, the covers on the left have expanding rubber seals to keep them in place.
This is a later model auctioned on eBay
This one dates from 1966/7 and belongs to Rodger Bean who has kindly forwarded some instructions.
John Hawkins was at HW Sullivan Ltd. at St Mary Cray between 1962 and 1972, and during that time, the company went through various purchases/amalgamations, including AVO, Thorn, George Kent, and The Cambridge Instrument company.
He started at 15yrs old as a capstan lathe operator, then worked on 2nd grade switches, engraving, worked in the resistance lab building decade resistance boxes, Capacitor lab assembling capacitance substitution boxes, Inductance lab wiring standard inductors into inductance bridges, BCS lab measuring inductances against standards, did some prototype assembly of circuit boards for the Sullivan Auto-balancing LCR bridge, and did repair and re-calibration work on various Sullivan instruments.
He worked on assembling and testing Cambridge portable pots and
still remembers the standard cell having 1.01859 volts at 20degrees C.
Using a diamond coated spatula on the windings of the 100 position dial
to make all the steps even and winding and assembling the multi-turn
rheostat.
Later, I was involved in repairing and re calibrating instruments made
by CROPICO and Tinsley, as well as our own Sullivan gems. He
particularly remembers the beautiful switches on the Tinsley 3 dial
vernier pot, and the Sullivan first grade switches with their silver
contacts.
Those 10 years at Sullivan’s were the happiest working days of his life. Everything was done in-house, there were only about 250 of us and with the exception of the chief engineer Mr Griffiths, they all knew each other by first name.
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