Sharp R1850 s/n 125758.
exhaust fan turned on all by it's self for the first time.
We have had this microwave for almost five years.
I was wondering anyone else has had this experience.
I suspect maybe the humidity sensor or the main control board may be faulty.
Please help if you are able.
Regards,
Tom

tom dunlap, January 2007

Chances are you have a bad hood thermostat or thermal cutout.

We have a service manual for a similar model on our site: http://www.microwavedisplay.com/r1380_r1381_sm.pdf

While you can't go by the part numbers in the above manual, you can use it for important safety, disassembly and test info.

You can order parts for Sharp models from Tritronics at http://www.wehaveparts.com.

You can find wiring diagrams and parts lists and order parts for most other brands from the Pros here: http://tinyurl.com/gv383.

William Miller † MicrowaveDisplay.com, March 2007