DWL wrote:it is much closer isnt it. It has arnex indented in the plastic crystal by the look of it. Mine has nothing. Is the date around the same time? Mexico Hughes Aug 75
regards
Adam
I supposed the name could of been rubbed off the crystal, this one is really faded, this was a very common case design used by several manufacturers so it might be hard to identify with 100% accuracy. The module inside the Arnex is a Hughes, Mexico, September 1975 so very very close to your date.