My audio cables that goes into my k2000 get quite hot about 50 degrees C. Is this a malfunctio or are they used to help cooling it?

This is perfectly normal. Right near your
audio outs is the power supply for the K2000. If you had upgraded your keyboard
recently and are now experiencing extreme
heat from that area though I would suggest
that you buy the fan kit. According to Kurzweils warranty the fan kit must be installed with any upgrade. this is because
some of the installed components in an upgrade generate their own heat. But if
this is not the case than again its perfectly
normal. Of course if your audio cables are
getting so hot that you can hardly touch them, I would strongly recommend to take
it in to a service center. Hope this info
helps.