Yes, there have been changes made to the design of the original
Macintosh Color Display.
The differences between the Macintosh Color Display, M1198LL /A and /B
monitors are that the /B monitor contains additional circuitry so that the
monitor is Energy Star compliant, which is a voluntary international
agreement that was signed in June 1993. This agreement focuses on making
electronic equipment more energy efficient.
Despite the circuitry difference, the monitor specifications and performance
is identical to the /A version. They use the exact same ciruitry that produces
the video signal and they use the same CRT.
These design changes are not unusual. It is Apple's policy to not only
manufacture monitors with the latest technology, but to also make
design improvements throughout the life of the product.
Article Change History:
21 October 1993 - added M1198LL /A and /B notations