Thorn 'SONPak 7' OT 70.4

Floodlight acquired in June 2013

My quest to acquire seemingly every SONPak floodlight ever made continues with this unused example from 1987; the same year that a certain Rick Astley's song "Never Gonna Give You Up" was released, and also the same year that one Michael Fish made a comment about the weather that has become somewhat infamous...


This version of the floodlight is little changed from its predecessors; the most noticeable difference is that the identification plate has been moved from the top of the reflector to a position adjacent the lamp in this version.


Once again, the floodlight body is of Glass Reinforced Plastic construction, while the support stirrup bracket is mild steel finished in black.


The GRP is of a slightly more polished appearance than the material employed in the 1983 and 1985 versions is.


The SONPak boasts an IP 65 rating (when the visor is in place and the screws secured) - an impressive statistic for a 1980s' luminaire, and one that placed it ahead of rival contemporary floodlights, including the GEC "Solarbeam 70" (IP 64), Philips SNF 200 (IP 55) and CU Phosco FL 320 (IP 44). The thick rubber gasket surrounding the visor is key to this achievement.


The patterned aluminium sheet used in the construction of this floodlight's reflector features slightly smaller dimples than appeared on earlier reflectors, although the patterning is not quite of the "bubbled" appearance of the reflector used in the 1990 version. A unique feature of this floodlight's reflector material is that the indentations on all sides of the reflector face outwards into the lamp area; on the 1982, 1983 and 1985 versions of this type of SONPak, the dimples on these face away from the lamp area. The 1990 version uses a mixture of both - the sides have the indentations facing into the lamp area, but the curved section behind the lamp have the indentations facing away from the lamp area...aren't you glad that I cleared that up - you'll sleep better now that you know the way that the dimples face in SONPak floodlights; I know I will!


The Thorn lamp supplied with this fitting carries a date code of '28' - April 1984 (or possibly 1992, though a lamp from this year would more likely have carried GE branding).


This is the first (and presently, the only) SONPak in the Collection to carry Thorn EMI branding. It is also the first in the Collection (chronologically) that doesn't actually carry the 'SONPak' name.


Removing the reflector reveals the internal wiring. In a change to the layout of the components in earlier versions, the ballast is now on the facing section of the gear tray, with the ignitor and capacitor located on the other side. This change was perhaps necessitated by the change to the G53438.4 ballast from the G53320.T ballast previously employed in these fittings.


Removing the gear tray allows the other two components to be seen - in the foreground is the G53353.4 ignitor, and behind that, the capacitor dated to May 1987. A rather strange reaction appears to have occurred between one of the ballast's fixing screws and the surrounding metal of the gear tray.


With the gear tray moved to one side, the two fixing brackets for it can be seen. These are held in place using the two bolts whose heads are mounted externally, and prevent the floodlight from rotating on its mounting bracket.

70 W SONPak Floodlights in the Collection

1982 1983 1985 1987 1990 1993 2000
Installation and Servicing Instructions




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