I like that slight ding sound as I move my hand and wrist too. It's the characteristic of the memovox. After the alarm has thrown/triggered, the hammer isn't locked down (by design or the lack of), and so with even the slightest wrist movement, the hammer will "kiss" the gong again. Since the alarm is a rather nice metal bell tone, I am actually quite fond of it. It's like wearing a living breathing watch
If you prefer your memovox to stop making those ding sound after the alarm has been thrown, simply move the alarm time to some time else, and then wind the alarm crown couple turns. That will be enough to lock down the hammer and shut it up.