Noise from Remstar Auto A-flex

[Greg Schultz]

When inhaling a noise comes from the machine  that I can best describe as a "faint howling of wolves". No noise when exhaling. I have switched masks, removed the humidifier, checked hoses, and have come to a conviction that the noise is coming from inside the machine.
The machine is about four and one half years old. The problem has existed for six months or so. Has anyone experienced this situation? Any DIY fixes? I have to wear earplugs to block the noise. Just loud enough to hear and continuous throughout the night. 
Is there any chance of exchange or new machine? This came as DME from Medicare and next January it will be renewable, if I can stand it that long.
Thanks for your ideas or comments!

[Sleeprider]

The only fix I know of to mitigate this is to enclose the machine in a drawer with the electrical and air-tube through a 2" hole in the back of the cabinet. That usually works. If you still hear it, then the solution is a warranty change of the machine. Most moaning, howling or high-pitched whine in a CPAP machine is a bad fan unit.

[Greg Schultz]

Thanks Sleeprider,
I'm so close to the 5-year machine turnover (Medicare) that I doubt I could get a hearing on the basis of warranty. The drawer idea has me thinking though!
Greg