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@djayhawk2020
See here for more info:
If you plan to upgrade your Apple Color Classic we show you what is possible by just switch to an other compatible board.
powercc.org
If your LC575 board runs @ 512 x 384 resolution, if running System 7.1 you might have a patched version of software (unlikely just this), and the "resistor move" mod is highly likely.
If running System 7.5 and above, you will definitely have the "resistor move" mod carried out; which will need to be reverted back to stock for an eventual 640 x 480 mod.
Once reverted back to stock, you can focus on the 640 x 480 mod; I recommend the "VGA mod" for simplicity and I've two CCs (Mystic and Tacky, recapped entirely) which work well with this mod, it can also be reversed relatively easily.
JB