What is the difference between a Commodore 1701 and 1702 monitor?
There is no appreciable difference between these monitors. The 1701 model changed to 1702 when Commodore began using a different picture tube supplier in late 1983. Cosmetically, it's nearly impossible to tell the two apart. They're virtually identical in appearance, and the electrical connections appear to be the same in both models. We have a number of both models here at COMPUTE!, and we've noticed that the resolution appears slightly sharper on the 1702s, but this is only because they're newer than the 1701s. (The color on a monitor gradually fades after prolonged use.)
Commodore also makes the 141 Color Monitor, essentially a 1702 with a charcoal gray color designed to match the Plus/4 and Commodore 16. It's compatible with the VIC-20 and 64. Commodore's newest monitor entries are the 1901 Monochrome Monitor and the 1902 RGBI/Composite Monitor. Each was announced at the Winter CES in support of the Commodore 128.