Update:
I found the Torx tamperproof bits at Lowe's Hardware for $8.00. It didn't include the screwdriver part, it was just six bits that fit into a hexagonal screwdriver part.
So I took off the marquee and found:
The buzzing sound from the marquee is definitely coming from the ballast. The ballast is labelled "Radionics 14-15-20 Watt". Radionics has a huge array of ballasts, so I could get a replacement, the question is, will it do any good? It's a different environment going from a noisy arcade or warehouse to a relatively quiet living room.
Regarding my bigger problem, the nasty speaker buzz, I inspected the connections and they all look sound. I measured the resistance across the speaker terminals at 8.3 ohms, where I expected 8 ohms. Is this normal? Would a cheap 8 ohm speaker work if it was plugged in, or would the buzzing stay?
One interesting phenomenon: When I unplugged the marquee light, the game started without my touching the start button (it's set on free play). Once it started by itself, the control panel wouldn't respond until I pressed the start button. If I plug the marquee in and unplug it again, nothing happens, but if I unplug the machine from the outlet, plug in the marquee, turn on power, then unplug the marquee, this happens again. Is this related?
Ken mentioned a possible "power supply capacitor and connector problem" How to diagnose this?
TIA,
Buddabing