Filastruder Wires burned

Hello ,

yesterday I found the wires that go to PID pin 8 and pin 9 burned (the one from motor switch to pin 9 and the bridge between pin 8/9), the PID almosted melted in the area near the connections, I replaced the wires and everything is working fine again.

it took me time to realize the burning odor is coming from the inside , I first thought it was the board , then noticed the struder is unable to reach temp, to open and discover it was almost going to ignite...

is this bad wire quality ? anything anywhere to inspect