Welcome to NLG Bo.
What you have there is a Summit Coin Limited machine. Made in the early '80s. I have a Summit machine although mine isn't a slant top, just a plain old upright. They are virtually impossible to get parts for.....sorry. Almost no literature, only made for a couple of years. As you can see made in Wales, for export to the U.S. market. I don't know the setup of the slant top but I'll add some pics of mine as even the video poker machines were almost identical inside. First, look for the fuse box. Maybe a long black unit with caps holding the fuses in. Mine had a couple of blown fuses and replacing them lit it up. Can you see if the reels have a green cord running around the sides which turn the reels? If those are broken, they will need to be replaced to make it run. But first you need to get it to come to life. My machine has vertical boards in the back. That run everything. There is likely one that has a battery on it. On mine I had to remove the boards and use spray contact cleaner on the pins the boards plug into and on the board connections themselves. After all that (and the new cords) mine came to life. Some more pics will help to see what's inside. Maybe I can help, but these machines are a pain.
I've put a pic of the reels and cords, the main board and the board location with the fuses and power switch below the boards. Let me know if I there is anything else I can do.
Dave