I just found this video showing a gradius arcade cabinet being switched on and then warmed up, from a few random dots in the screen to the konami morning song, and then the attract mode of gradius: And this endlessly fascinates me, in no small part because I'm not much knowledgable in how electronics works, and I was wondering what is the exact process. Like, What makes those dots appear on the screen when the cabinet is switched on? What is used to trigger the Presented by konami and countdown voices? How does the game's software knows when it can safely render the text for the warmup countdown and play the bgm, and how does it know that it can stop playing the audio cues? Stuff like this gets me really curious. EDIT: Did the game know while warming up if some of the data had gone corrupted? EDIT 2: Why is there those weird vertical refresh lines just before the visual countdown is loaded?
Dots look like video artifacts from the ram. the main storage is bubble, but it probably has a smaller system to manage the startup, with it using the voice chip to read out the status.