Krell ksa 100 shuts off

I got willed a KSA 100 amp. It runs for about 5 songs before you hear a click and it shuts down. The green led on the power switch goes dark.

Then about ten minutes later it comes on again by itself.

Is this a thermal protection circuit kicking in or does this amp need service?

FYI I am using a balanced Audio VK3 and a Aria CD player hybrid.

Thanks.