I've had an Apple IIc Plus for a few years now and everything seems to work fine on it. I use it several times a week for programming and gaming and never had a noticeable problem. I've ran the diagnostic self-test on it occasionally over time and always came up with the same result, which now I'm beginning to question. At the end of the test, I see "SYSTEM OK" but there are a lot of other garbage characters on the screen. Question is, is this normal or do I have an issue somewhere?