It could have been also when you were trying to track the blades that the tail rotor got caught up on something and stalled. Like if it was sitting on the carpet, and the tail skid poked down into the carpet and made the rotor bind on the carpet, or grass would do the same thing.

What part of the boom was warm?

oh and BTW I did an ohm test on my boom like choppersrule said, and I was expecting it to be lower, but I got about 70 ohms.