Had something similar happen to my LA-1K after about an hour of use(it was just a few days old). One of the LDMOS's died. I called Palstar, we ran some tests and I was told to send it back. So I boxed it up and $45 later it was on the way to Palstar. With-in a week the amp was back in the shack. Palstar paid for return shipping. While I run mine off of 120v, it is used nearly all day long and has been cycled tens of thousands of times. I've even configured fans on both sides of the amp in a push pull configuration. I've only seen it hit 70c once. I guess what I am getting at is once they get yours working, you will not be able to kill the thing.
Good luck with it,
John / AI4FR
John - AI4FR