Have you checked the connectors to the plugs for a bridged connection? A piece of metal or stray solder could be causing the issue.

It could also be an internal crack in one of the wires.

I have on occasion found a short within the wiring bundle. If you've narrowed it down to one plug that is a good place to start. One game I had there was a sharp angle in the bundle near the edge of the play field. Raising and lowering the play field over the course of 50 years caused some of the cloth covered wires to fray away and make contact with each other.

Without knowing the exact issue or what's on the plug it's hard to give good direction, but here is the first thing I would try.

If it only blows when the plug is plugged into the backbox then it is probably not the harness, but something from the backbox connection to somewhere in the backbox.

Get you multimeter and set it for continuity (buzz when shorted)

There are 2 commons, One for 6 volts and the other for 24 volts.

Connect one side of the meter to the common that is connecting all of the lights together and then touch the other end to each of the plug connections.

See if you get a short. If you get a tone then it's one of 2 things. It could be the actual wire that is the common or it's your problem.

You can always disconnect the wire and see if the fuse blows which tells you the definitive answer.

Now you have to start digging and trying to trace the color.

You then have to do it for the common on the 24v side. You can usually find it by looking for a common wire running between the coils of multiple switches. The same test and results apply here.

Couple other things about the 24v side. When checking continuity you will get a tone when going thru a coil.

You can narrow down if it's a coil or a true short by checking the resistance.

Coils will have varied resistance while a short will show zero.

Hope this helps.

Bert

Have you actually checked all the coils? I seem to remember in another thread that you said you had a score reel solenoid that locked on.

You can't just look at it to tell if it's bad. You have to put the DMM on them.

If it's blowing on start up that is suspicious for a bad coil/solenoid.

https://pinside.com/pinball/forum/topic/68-williams-cabaret-blowing-24v-fuse

This is where you said one score reel coil was buzzing and not moving.

A fried score reel coil would blow a fuse on start up because it's effectively a dead short. Resistance check is much more important than a continuity check.

I think checking continuity throughout the game can be misleading as you have many make and break switches that change current path.

Shorts are tough to find. Divide and conquer is usually my approach. That and a very through visual inspection usually finds the culprit.

Make a circuit breaker. It pays for itself in one use:
http://www.pinwiki.com/wiki/index.php?title=EM_Repair#Electrical_short_troubleshooting_Fuse_helper

In the past, I have even been tempted to de-solder strategic chunks of a circuit to find the short. I've probably had to track down 15-20 over the years. Invariably, I find it through a visual inspection.

They all have the yellow wire in common.

Your YouTube has be disabled by the owner for play back on other site. Your link does not work.

I would starting from scratch here.
When you turn on the machine, the fuse stays intact?
So at what point does the fuse blow? Does the game reset, or does it blow before resetting is complete. Try and identify what is happening when the fuse blows.
Do all the score reels reset at the same time, or do 1 and 2 move together, then 3 and four?
Do you have a schematic for this game? I have others schematics for games of the same era, if you have a PDF version of the schematic, I would love a copy

Found the YouTube, anyone wants to watch go to youtube and put this in the search "hO8KzlGZv_k".

Your youtube does answer some of my questions.

wow that video, man it was hard to watch. that said you did some things right like removing the playfield. but this is what i would do.

1. turn the game on with fuse/breaker installed for the coil fuse.
2. go to the backbox.
3. reset the player unit (to player 1 which is the reset position.)
4. manually press the 1 pt relay. the reel should advance.
5. repeat with the 10 pt and 100 pt relays. again reels should advance. Keep pressing the 100 pt relay (when the 100 reel gets to "9", it should advance the thousand reel, which is what you want.)

if the coil fuse/breaker blows, then you have a score reel coil burnt/shorted.
if all the reels move, then advance the player unit one step (player2) and repeat steps 4 & 5. Do this for players 2,3 and 4.

note the 1 or 10 point relay should advance the match unit. this could also be a problem, and you'll know it as soon as that point relay tries to advance that stepper.

i suspect you'll find a problem doing this. report back.

If you can scan the part of the schematic that has the start button (replay button), and post here. included the black and yellow wires (Top and middle). If you can scan the whole schematic, I will PM you an email address to send to. I will also upload to IPDB.

With the schematic we can quickly isolate the area. From your Vid above, I don't think you are getting anything to happen. I think the fault is in the bit of circuit I'm requesting above.

I believe the entire switch stack needs to be between the two posts, not with both posts on one side.

http://www.pinrepair.com/em/index3.htm#free

So I suspect what was happening is that the post was jamming the top switch stack (which is connected to each other) to the bottom switch stack and shorting the thing out. If the posts were in the correct position, they probably would not over travel like that. Note where the posts are in the above picture.