Classic on October 15, 1990. This made the Macintosh Plus the longest-produced Macintosh model, having been on sale unchanged for 1,734 days, a record not surpassed until the second-generation Mac Pro in 2018. It continued to be supported by versions of the classic Mac OS up to version 7.5.5, released in 1996. Additionally, during its period of general market relevance, it was heavily discounted like the 512K/512Ke before it and offered to the educational market badged as the "Macintosh Plus ED". Due to its popularity, long life and its introduction of many features that would become mainstays of the Macintosh platform for years, the Plus was a common "base model" for many software and hardware products. Problems The lack of fan could cause the life of a Macintosh Plus to end early for some users. As the power supply would heat up, solder joints inside it would fracture, causing many problems, such as loss of deflection in the monitor or a complete loss of power. As in most early compact Macs, the problem was common in the yoke connector, flyback transformer, and horizontal drive coupling capacitor. A fan was also often added to reduce heat when the machine was upgraded to its full RAM capacity of 4 MB. From the debut of the Macintosh 128K through the Macintosh Plus, various third-party cooling add-ons were available to help increase airflow through the unit. Apple reorganized the compact Macintosh case to accommodate a fan with the release of the Macintosh SE, which optionally included a heat-generating internal hard disk. ROM revisions The Plus went through two ROM revisions during its general market relevance. The initial ROM was replaced after the first two months as it had a serious bug which prevented the Mac from booting if an external SCSI device was powered off. The second revision fixed a problem with some SCSI devices that could send the Mac into an endless reset at POST. Emulators MESS Mini vMac Spectre GCR Timeline References External links Macintosh Plus technical specifications at apple.com BYTE takes an early look at the Mac Plus Plus Plus Computer-related introductions in 1986