Apple introduced the Macintosh Plus on January 16, 1986 as a replacement for the Macintosh 512K. The Macintosh Plus has an 8 MHz 68000 processor and an internal 800K floppy disk drive.
The Plus supports up to 4 MB of RAM. My Macintosh Plus has only 1 MB of RAM and is branded “Macintosh Plus 1 MB” on the back of the computer. I purchased it in 2006 on eBay for way too much money, but it is a very well preserved Plus, almost unused.
This Mac is a later model Plus with the “platinum” colored case. Platinum was Apple’s term for their light gray-blue cases. Originally the Plus was beige like the 512K, 512Ke, and 128K.
This case color was pervasive at Apple Computer from the late 1980s through to the introduction of the iMac in 1998. Another example of a beige chassis turned platinum during this time is the Apple IIe Platinum.
Mac Plus in Detail
The Plus is a significant improvement over the previous compact Macs primarily due to the addition of the SCSI bus.
Previous Macs did not have SCSI, thus making it more difficult to find a suitable external hard drive able to connect through the drive port, the printer port, or the modem port.
These drives are considerably slower (as much as 4 times slower) than external SCSI hard drives. My Plus has an external Cutting Edge 30 MB SCSI hard drive.
The Mac Plus does not have the capacity (no connector on the motherboard) to add an internal hard drive like those found in the Macintosh SE and later compact Macs, nor does it support a 1.4 MB high-density external or internal floppy drive.
The Plus has the following ports: one DB-9 mouse port, one DB-19 disk drive port, one DB-25 SCSI port, one serial DIN-8 RS-422 printer port, one serial DIN-8 RS-422 modem port, and an audio out port. The Plus does not have an internal microphone or microphone port.
The keyboard is connected on the front of the computer using the same connector as previous Macs.
It is similar to an RJ-11 telephone connector. The keyboard is an extended version of the original Macintosh keyboard, complete with cursor keys and a numeric keypad.
The Plus does not have ADB (Apple Desktop Bus) like later compact Macs beginning with the Macintosh SE. It uses Apple’s original, somewhat clunky, DB-9 mouse.