MSDs (and I'm sure others but I despise MSD) have been known to not work out of the box. I've said it before and I'll say it again, I've had 2 6AL boxes not work, one of them just like yours where it fired up, then something inside the box fried, but in that case it smoked quite a bit so it was pretty obvious that it was the box. After that one I switched to a stock MP electronic setup and no problems in 10+ years.