Hunts Model CRB Capacitor Analyser & Resistance bridge

Serial number 1015

This instrument was a gift from Fred Standley and Sons of Wymondham, Norfolk.

This is a view of the inside, the half wave metal rectifier for the HT supply is the tubular component at the bottom of this view.

This is a view of the inside of the instrument looking down from the top. The transformer fitted when I received the instrument appeared to have been rewound and was it was soon apparent that one winding (that for the HT had been omitted). A search on the internet located an instruction manual which included a circuit diagram which was helpful, though it did not show the what the voltages of the secondaries should have been.

A preliminary check using an external DC supply of about 200 volts showed that the instrument had promise, the neon lit up as did the magic eye on which the shadow could be varied. I had a transformer from a butchered Mullard GM4140 Capacitance/Resistance Bridge which was much the same size so this was pressed into service. The 4 and 6 volt windings in series were used to supply the bridge and one side of the 250-0-250 volt was wired to the rectifier to supply the HT. The other 6 volt winding was wired to the heater of the Y63 tuning indicator. It now works, though maybe not as well as it did originally.

A H Hunt Ltd. The company was founded in 1901 and was a major manufacturer of capacitors. These were made in Wrexham and Yarmouth, though earlier they operated in Croydon. The firm was taken over by Erie in 1967. There is an interesting thread here. This instrument was made at Bendon Valley, Garratt Lane, Wandsworth, London W18. in about 1945/6. You can find an instruction manual here