Had slightly leaky battery in compartment, and rust on rear ports. Unfortunately, something leaked badly and rusted the internal frame and damaged the logic board. Cleaned logic board thoroughly and will try with analog board, as well as with another, known good Plus' analog board.

The first Mac that was genuinely good enough. The Plus shipped with 1MB of RAM standard, a double-sided 800K floppy, and — crucially — a SCSI port for external storage. Sold continuously for three years and six months, longer than any other Mac before it. Apple manufactured so many that a Plus often costs less than a Classic today, despite being older. The machine that proved the Macintosh concept was commercially sustainable.

• EveryMac