It does sound like your transformer has fried. This is a very rare problem, but it can happen.

In the USA, the primary side of the transformer is designed for 120 VAC at 60 Hz. I'm assuming that you are in Europe because you are using a 50 Hz transformer.

In any event, you can definitely replace it. These were large and rugged transformers that were made by the Electrical Windings Co in Chicago, who specialized in producing transformers for the local pinball factories. If possible, you should try to find a used transformer of the same type, perhaps from a salvage parts game that someone is selling.

These transformers rarely go bad, so it is possible to get one from a game that was scrapped for other reasons. Because of the very high output current that these transformers need to supply, I think finding a used factory original is the best way to go.

While it is possible in theory to replace your game transformer with a new one, it can be challenging to find a new transformer with the necessary output current. As far as I can tell, the original Williams EM transformer could supply at least 20 amps at 6 volts, and 15 amps at 28 volts. So, if you are going install a new transformer, it would need to provide this kind of output power.

- TimMe

Just to add a bit more information on this - the secondary of these transformers provided two output voltages: 6 VAC at 20 amps or more (for the lamps), and 24 to 28 VAC at 15 amps or more (for the coils).

Also, I should also mention that any salvage Gottlieb EM transformer from the 1970s would also work as a replacement. While some may cringe at the idea of a Gottlieb transformer in a Williams game, at least it would get your game working.

Note that you could not use a salvage Bally EM transformer as a replacement, however, because the coil output on these was at 55 volts rather than the 28 volts used by Gottlieb and Williams.

- TimMe

Arcing doesn't imply a short, but if you're blowing a fuse something is going on. The switch is driving the Match Unit solenoid.
Stardust 10 pt relay (resized).jpg
Does the Match Unit advance every time you score 10 points? Is the solenoid an A-22-550 coil? How does it look?

/Mark

One thing to remember on these Williams woodrails is that the high tap is selected by inserting the fuse in the high tap slot. You can not have fuses in both slots, so either the normal, or high tap fuse holder must remain empty.

Williams went from 50V to 24V.
That looks like a more modern coil. It could be incorrect for that game.

That's not much to go on. Does it try to advance when the 10 point relay fires? Does it advance if you push the plunger in manually?

If you desolder one of the wires to the coil does the problem go away? If not the coil could be fine but you might have a short elsewhere.

An A-23-600 coil has a slightly higher resistance than the A-22-550 on the schematic. But if the coil is damaged its resistance could be much lower and it could blow the fuse. What's the resistance of the coil? It should be a little over 3 ohms according to https://www.flippers.com/coil-resistance.html.

The missing teeth keep the Player Unit from stepping to player 5.

Check the resistance of that coil. There is a chart online that has the approximate DC resistance of most coils. If it’s close, then it’s something else. If the resistance is low (like 1 ohm or less), then that could be your short. Depending on where you disconnected the wire, it could still be something that’s not the coil, such as another tie point or broken insulation allowing the wire to touch another connection. The problem with a short circuit is that it’s not shown on any schematic. Also remember that a schematic is a logical representation of the connections, not a physical layout. Just because it shows a connection between a switch and a coil doesn’t mean it doesn’t go through a Jones plug or a tie point, etc. Youre making progress with your isolation, so that’s good.

Good luck,

Dave

Sorry but that was a mistake. This forum is full of posts from people who tried shotgun cleaning & adjustments, and caused more problems than they were originally trying to solve.
What to do instead: Slowly and carefully diagnose one problem at a time and then fix only that.
http://www.pinrepair.com/em/index2.htm#clean

If pressing the Replay button doesn't activate the Replay relay, Inspect and diagnose this circuit with Alligator clip jumper wires

https://pinside.com/pinball/forum/topic/gottlieb-big-shot-repair#post-6305153
http://www.planetimming.com/Pinball/troubleshooting/EM%20Troubleshooting.pdf
http://www.pinrepair.com/em/index3.htm#features
Example of a pinsider actually doing this https://pinside.com/pinball/forum/topic/red-baron-tech-question#post-5858156

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