The Macintosh Color Classic has been and still is one of the most popular computers ever produced — next to the iMac, of course! Apple released their first "compact" computer back in 1984. The Macintosh 128k paved the way for its successors, including the Color Classic. The Color Classic (Performa 250) is a 68030/16MHz and was released in early 1993. The Color Classic II (Performa 275) is a 68030/33MHz and was released early in 1994 (but ONLY in Asia). :(
Besides the slow processor, the greatest bottleneck of the Color Classic is the 512x384 (560x384 max) screen resolution. Most CD-ROM games and some applications for the Mac require a 640x480 resolution or higher! :(
You may be asking yourself, "What's the point of increasing the screen resolution if the system itself is only 16MHz??" Many people do this screen resolution upgrade because they plan on adding a 575 logic board (68040/66MHz) or modifying it even more to accept a PowerPC logic board.
The original plans/idea for this modification came from Takashi Imai's website. I created this website because I thought pictures would help (always do!) and a clearer explanation of the details was needed.
The hardware specification of the Color Classic is LC based — meaning 640x480 is possible. However, there is one obstacle to overcome regarding the built-in monitor — the frequency differences. The Color Classic has a 10 inch Sony Trinitron CRT display with a vertical frequency of 24.48KHz and a horizontal frequency of 60.15Hz. It is identical in these respects to the original Apple 12-inch RGB monitor. The now-standard Apple 13-inch High-Res RGB monitor (and newer models) uses a vertical frequency of 66.67Hz and a horizontal frequency of 35.0KHz.
In order to solve this discrepency, you must raise the horizontal scan voltage from 60V to 84V.