[Arran]

As far as I know the Coronado sets were sold by the Gamble-Skogmo department store chain. I don't know who actually manufactured them, probably Wells Gardner, Belmont, Continental Radio & Television, and other private lable radio makers. The schematics are always listed under Gamble-Skogmo if you need to find one.
Is the speaker missing from the Silvertone? Is that why you need one?
Regards
Arran