Hello, my name is***** to Justanswer! Give me just a few minutes to look up some specifics, I'm working on this now.
Do the headphones produce sound when it shuts off? Does the screen still function, only the sound cuts out?
Let me know, that's a good test of all of the parts of the keyboard.
Ok, now how about a demo song, or percussion? Any sounds from the machine at all?
Ok, let me think on this for a while. At first though, I think you have a processor that is hanging up, which is not good. That requires special equipment to solder a new one in, and it isn't cheap. Let me wrap my brain around the symptoms and see if I can think of something else to try first. At this point, I think you will need a Kurzweil repair shop to fix the processor. I say it's a processor because it fixes itself when you turn it off and on. I also want you to do a hard reset, sometimes that's all it takes.
There are heat sinks, but most models don't have a fan. You can remove the cover by removing the screws from the bottom of the piano to take a look, but I don't believe that model has a fan. If a fan went out, there would be a sensor that shuts down the entire piano. Since the other functions work, it's telling me that a processor is getting hung up. Wouldn't you agree that an hour is a long time for a fan not to work? It's the IC that sends signal to your amp circuits that is getting stuck. That would explain why everything else works. The IC that is after the motherboard, tone generator and processing mixes all of the audio and sends it to your amp circuits. If that gets stuck, it results in no sound.
These are the three closest service centers:
Name:Commercial Audio Inc.
Location:Myrtle Beach SC 29577 United States
Name:Pro-Audio & Keyboard Service Center
Address:3021-1 Stoneybrook Drive
Location:Raleigh NC 27604 United States
Name:Tritech Electronics, Inc.
Location:Greensboro NC 27405 United States