The key to EM's is and always will be PATIENCE.
I do not know if you have ever fully shopped the machine but that is also key to keep a machine 35+ years old going 100%. A 4 player shop job generally takes me 100+ hours to go thru everything.
Williams EM's are very dependable machines once you have them dialed in, way more so then Gottlieb IMHO. I shopped my Space Odyssey when I first bought over a year ago and still no problems, yes over a year!
The guy who will do the best job working on the machine is you, and only you. Anyone else will just come over fix the immediate problem then a month later you will be back to square one with it not working.
Get yourself a TOP 1 video and a Manual on EM repair like I did and it will help you immensely.
I too was like you when I had my first EM but at $75.00 an hour for a repair guy I did not trust, I knew I had to do it all myself and have.
The guys on this forum will help you when you need information on a problem so no worries, just get your EM tools out and be prepared when the advice comes.
Ken