Hello, I own the above referenced Mac. The serial number indicates that the computer has produced in the sixth week of 1984. An expert, online, who has seen pictures of the machine, says that the on/off button indicates that the power source is from 1987-1992. Another expert says that, because there are no red lights seen inside the floppy drive slot, the machine must have an upgraded hard drive. The computer has never left my family's house since it was brought home in 1984 and it has never been opened. It is a Drexel University model--very rare. Drexel was the first college to require incoming students to buy a Mac in 1984. Were these models delivered with a 512k hard drive in a 128k case and is the statement about the on/off button true? Thanks.