Wouldn't Heat - Fried Wire - Replaced - Now Blows Circuit

We have a DE312 Dryer. Takes a lickin’ and keeps on tickin – probanbly 20 years now. I love it and keep fixing it.

Here’s what happened. I’m trying to figure out the scenario that might have made it fail, and how to fix it.

I threw a load of clothes in, started it up, came back, and it wasn’t hot, but it was running.
The whole heating tube was replaced a couple of years ago.
I opened it up and started testing components.
Fuse was okay.
Then I went for the hi limit thermostat and noticed the wire from the switch to the heater terminal was fried. Literally – green corrosive dust and fried into two pieces. Electromigration? / I don’t know.

I tested the thermostat anyway, It was fine. I put it on a hot plate, and it seemed to open and close correctly.

I ordered an official jumper wire and just replaced it.
I plugged it back in and pushed the start button.

It blew the circuit right away.

(have since tested cycling thermostat – its good as well)
Any Ideas?

Thanks… …Mike