Thanks, Joe, for your detailed instructions. Regarding the date of my machine, I have keyed in the serial number and got the date of 1961. The serial number starts with JE, which was made in Scotland, I think, and the number was issued in 1961. So why would ISMACS say it was made in the 70's? And the machine isn't green, but is a gray color.
There's an ebay listing for one identical to mine.