https://en.wikipedia.org/wiki/Lectron#/media/File:Egger-Lect...
(Mine was branded Braun, not Raytheon. not sure if that because the Braun branded versions got sold in Australia, or if dad got it in Germany or Europe - he travelled there for work quite a bit during his career.)
It had a great 10-year-old friendly manual, which I can't seem to fond anywhere, except for this pic:
https://www.radiofundgrube.de/bilder/expkasten/zoom/braun_le...