HL Tiger, completely dismantled on the working table: I wanted to measure the voltage at the shooting led, but was unaware that the gun motor was stuck jammed.
Nevertheless I went on keeping the firing stick pushed to keep the led lit while measuring the voltage... until I started smelling something was burning onto the main board.
Result: almost completely burn the gun-related resistor.
Was lucky tho, I just had to change it and everything else worked fine. A couple more seconds and I would have fried the whole board maybe.

One more: during the first runs outside, I heard a strange ticking rumor coming from the tracks but didn't mind to check. The left track was running badly aligned with the sprocket (the track theeth caught in the middle of it) and I run and run until i dropped the whole track on the grass... my first track section broken.
Now I pay an utmost attention at track noise while running outside.