Slow down a bit. Transformers are a hardy lot, they can take a pretty good beating.

First things first. Fixing a broken ground braid in and of itself will NOT burn up anything.

Reconnecting a broken ground braid that has a short to power somewhere down the line can/will break something. Especially if said short is before any fusing.

Open your prints, disconnect all the transformer outputs that go to the cab, power supply and logic.
Use a voltmeter and test every single output of said transformer.
If one is missing, stop here. If all are in tolerance, continue.
Carefully look at everywhere the braid goes and see if it is loose or jammed against something that has voltage normally.
If clean to this point, reconnect the A/C lines from the transformer to the power supply (power off of course).
You can leave all logic disconnected.
Turn on power and verify all power supply outputs.

At this point, also use your meter on voltage setting and check the ground braids for power using your black lead on where the line cord connects to the cab.
Voltage setting on ac or dc don't really matter just set it to auto and high.
You should see NO voltage on anything with a braid or metal in the cab or on the playfield.
Don't forget to test your lock bar, your coin door, your playfield supports, your side-rails and both sides of your broken braids.

Thanks Tony.

And to add to that,,, if you did, someone may have hacked the ground braids to 'work around' the issue thus causing a reallllly bad situation that you inadvertently found out. Luckily.

Do the tests. Let us know.

And yes, by prints, I mean schematics. Old school term.