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  • Apple IIe colors wrong (timing problem)

    From Mitchell Spector@21:1/5 to All on Wed Jun 15 16:21:59 2022
    Is there a way to adjust the color phase shift timing on the Apple IIe? Oddly BOTH my Apple IIe's (different revision motherboards) do not
    display colors correctly. In Hi-Res, blue is turquoise, violet is dark
    purple, and green appears a sickly brownish-green. I can "correct"
    this by adjusting the tint/hue on my composite displays, but found
    it strange two separate Apple IIe's would have an identical problem.

    By contrast, my Apple II Plus, my 3 Apple IIc's, Apple IIc Plus
    and IIGSes display colors properly without any display adjustment.

    On the Apple II Plus there is a trim-pot to adjust the timing, but
    none on the Apple IIe. Just wondering how to correct this problem,
    could there be a faulty IC or crystal affecting the color timing?

    Mitchell Spector

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  • From retrogear@21:1/5 to All on Mon Jun 20 03:18:25 2022
    Comparing the Apple II+ and IIe schematics, it would be a matter of adding a trimmer cap across the C32 L3 3.58Mhz bandpass tuning.
    See page 36 of the IIe Sams ComputerFacts. What it does is change the phase of the color burst being generated.
    Or try another 14.318 crystal. The 3.58 is divided down from it.

    Larry G

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