I have a GE Advantium 120, model #SCA1000DBB 03 (JAN 2002). For several months, a periodic grinding noise lasting less than a minute was heard coming from the direction of the upper vents. Now, it is constant. The sound is more or less rhythmic, pulsing every second or so. When I unplug the appliance and plug it in again, there is no sound. Once I set the clock (which I must do, have to complete this step), the grinding noise starts. I discovered a temporary workaround: pressing "oven/bake" then start, then off, will disengage the grinding noise almost exactly 10 minutes, then it starts up again. I pulled off the grill and all fans I see are not moving. I pulled off the control panel and started it up. Probably dumb, but I had to see. But nothing was moving way back in there. This noise happens whether or not anything except the oven/bake function is used. The unit still turns, cooks, does everything it's supposed to. But the constant noise is scary and the unit is currently unplugged. I have looked for any others with a similar problem but cannot find a solution anywhere. Any help is appreciated.

Mark