Modern pachinkos actually are all electronic with lights, sound/music, and LCD screens. A pachislo is basically a slot machine, but a whole lot more fun than the US ones. Lots of LCD video animation, flashing lights, and cool music.
I'm not sure if there are fraud attempts. At least not with the pachinko balls. You buy them for about 4x what you will get back if you try to cash them in. The prizes are not worth much. The secret is that you choose specific prizes (cigaretts, medallions, etc.) and then take them to the back alley and trade them in for cash. It gets around the anti-gambling laws in Japan, but everyone knows this is how you do it.
The balls are engraved with the logo or name of the Japanese pachinko parlor.