OT: Fixing Listening Room Hum with a Ceiling Fan Cap


Living in a 20 year old home has disadvantages, if you happen to be the owner when the appliances all start to fail together.  

I was pretty sure this was the case with my ceiling fans.  Besides humming loudly one failed to start without pushing.  End of the line I thought. 

I was wrong, the humming and low torque were caused by degraded motor capacitors.  In our world metalized polypropelyne capacitors almost never fail, especially in a speaker crossover, but I guess the continuous use in series with an AC current wears these out early.

I had always thought that a humming ceiling fan was normal for an old fan.  I was wrong, it's not.  Replaced my caps and my listening room is much quieter! 

erik_squires

Interesting post. Seems like they all hum eventually. I would never have thought to look for caps in a fan. Good of you to figure that one out. 

@billpete  

Of the 3 fans inside it fixed the hum in 2 of them.  However, measuring the caps, all were significantly out of spec, measuring far too little uF and often too high an ESR as well.  So, if you have an older fan and it hums it’s probably time to replace the caps even if they don’t eliminate your hum. $20 and 20 minutes with many models, though easier if you have the kind without lights.