How do you know if an amplifier is blown?

I was wondering if there is something i can do to be able to tell for sure whether my amp is blown or not? And if possible a way to repair it and an estimate at how much it will cost? The amp is an mtx ta2301 one channel class d amp. I have been using it for a couple months in my old car and then i took it out to put it in my new car, so i put it in my new car and it turns on and plays and then it starts sounding messed up and then it cuts out and doesn't turn back on. I look in my trunk and find that the negative speaker wire came out from the terminal cup on the sub box and went to the positive.

when you wires touched together the amp should have went into protection and not harm it. the cutting out of the amp sounds like it could be lack of power. what gauge of wire are you using to powering it? use no less than 8 guage. and make sure the power and ground wires are making a solid contact at all points.

i wished it went into protection mode, but i unplugged it and put in my other amp which is a 4 channel amp and it turned right on. so unless im missing something i have a $100 paper weight. (I also checked the fuses on the amp and they looked good, but i still changed them to make sure and it still didn't work) I opened up the amp to look for burnt components or disconnected components and couldnt find any at all, it looked perfect inside. So now im clueless about what happened.

I don't know the cost of that amp, but you probally can get it repaired for around $80 to $100. Get it checked by somebody that knows what to look for first. '85 Toy

that wouldn't be worth it, i payed $100 for it, but it worked beautifully until it died.