Thorn 'SONPak 7' OT 70.4

Floodlight acquired in March 2015.

There are very few differences between this SONPak and the example made three years earlier, though by the time that this example was produced, the design was approaching eleven years old, and Thorn Lighting itself had undergone considerable changes, having completed the sale of its lamp division to General Electric of the USA in July 1992. Additionally, the SONPak range had been expanded, with units available that could cater for higher-wattage lamps.

Unlike the majority of the SONPak floodlights in the collection, this example has seen use, although this must have been in a reasonably dry location, as it is still clean externally, and the GRP body is not shedding fibres. A small length of flexible cable and a contemporary plug were supplied with the floodlight, suggesting that it was connected using a locally-positioned socket.


The fixing bracket supplied with the floodlight is perhaps not original (unless Thorn had altered the design) - the bracket's depth is much shallower than that of the brackets from earlier SONPaks, and rather than the bracket being of a single strip of steel that was bent into shape, this bracket is formed of three steel sections that have been welded together.


This view demonstrates the close proximity of the back of the floodlight to the bracket section.


The identification label is now situated in the centre of the underside section of the floodlight, alongside the cable entry point. This is the first SONPak that doesn't carry an acknowledgement of being British-made (though it still will be); instead, it carries the more generic 'Made in E.C.'. This stance was perhaps taken owing to some of Thorn's product range by then (specifically, those products that arrived in the range through the company's earlier purchasing of Europhane) being of foreign origin, whilst the company was keen to continue its 'British' image; thus, labelling all of its products as being made in the European Commission, in order that buyers wouldn't know a product's exact origin.


A GE-made lamp dating from December 2012 is fitted. Notice the somewhat off-centred appearance of the lamp's arc tube in comparison to the reflector - these fittings were designed for Thorn's own range of SON lamps, of course, and the arc tubes in these are set further towards the cap than the arc tubes of other manufacturers are. I doubt that there would be any noticeable difference in output, however, especially as the reflector material has a random pattern pressed into it, rather than being engineered to exacting focal positions.


Removing the reflector reveals the supply cable termination block, as well as the G53438.4 ballast.


Owing to the removal of a dedicated plate for accommodating the control gear components, the only means now for accessing the capacitor and ignitor is to remove the ballast. This is a fiddly enough process when the floodlight is on the ground, and the fixing screws are positioned vertically - with the floodlight installed at a height, and the fixing screws positioned horizontally, this process must be especially awkward. Incidentally, the capacitor is dated to March 1993.


70 W SONPak Floodlights in the Collection

1982 1983 1985 1987 1990 1993 2000
Installation and Servicing Instructions




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