Looking at the schematic we see two main paths: 10 amp fuse -> brown and 15 amp fuse -> blue.

Based on what is lit by blue / brown is your outage confined to one of those paths?

Double-check and reseat all jones plugs while you are at it.

triple_strike (resized).png

Check those fuses with a meter & like Dr_nybble suggested reseat the connectors.

That happened to me too. Is the machine plug wired correctly, is it the original plug? Is it a three prong plug? I changed the plug on my Silverball Mania, and wasn't aware it had to be wired a specific way. It turned out it was backward, and I was having trouble with a short in a light fixture, which would in turn blow the circuit breaker on the house current. When I went to change the fuse for the GI lighting, it was right next to the 240 Volt fuse line. I got the full jolt of 240 Volts, and it caused quite an arc from my arm to the fuse holder. I also wound up burning out each and every GI light bulb. Once I learned that the plug was wrong, I fixed it, and had to change about 60 lights in the machine. I learned my lesson that day, too!

Look at the schematic. The 10 amp line voltage fuse is before the master power switch.

Yep, rule of thumb (no shock pun intended) is that the line fuse is usually always live even when the game is switched off. If you want to mess with that you'll definitely need to unplug the machine and honestly it's always a good idea to unplug the machine when working on it at all (I don't practice what I preach but I've also been doing this for a while, but even then...), there is a ton of 120V circuitry running around in spots, ESPECIALLY in the pre-late-60's games (probably like 1967 and older, obviously varies) which were made before they realized they should probably cut down on it. Even on the newer games though it is still present not only in the always-live service outlet but also through score motor switches and the like. Relay bank reset coils are also always usually 120v powered.

In EMs, 120v lines are *usually* (NOT ALWAYS) rubber-coated/rubber-insulated wire rather than cloth-covered to avoid shock risk, so they're pretty easy to pick out when visible. (Of course it doesn't help you in the later Bally EMs when they made the transition to full usage of rubber-coated/rubber-insulated wire)

But yes, that fuse is live when the machine is powered off because the game's service outlet needs a fuse obviously and the service outlet needs to be powered when the game is switched off for service. Which also lets you know to never rely on the machine's power switch while you sleep at night, although many here do, I would never trust it as there is still very much "live" in these dusty old often-questionable machines even with the main power switch off.

Is that fuse for a light circuit? Check every single light socket. You may have accidently bent one of the sockets a bit causing it to short.

One of those fuses is for the backbox lighting, and one is for the playfield lighting. Make sure you're looking in the "dead" one, which is seems you are - just saying, rule out the backbox. Also, measure the voltage on the playfield GI line with the fuse blown and make sure you get a 0 reading rather than an extra 6 volts or 30v solenoid voltage, which would mean something is touching against the line. A lot more common than you think. It could also be against a lit "feature" light which may not show up on the GI line, so you could measure it on the empty fuse block (side that needs the fuse to get power, NOT the hot side) and finding ground on the transformer.

Hey Don,
if you have not got this resolved yet, unplug the coin door and turn it on.
it cud be in the door parts also. just a guess