Ceiling Fan/Light Pops When Powered Off

Riddle me this...
I have a fan/light combo unit controlled by a standard toggle wall switch. The unit is well over 20 years old.
4 position pull chain for fan - high, medium, low, off 4 position pull chain for 4 bulb fixture - 2 on - 2 off, swap the offs for ons, all 4 on, off.
Here's the problem:
If all four lights are off, the unit makes a single POP when I throw the wall switch to the off position. The sound comes from the unit, not the switch.
If any of of the lights are on, I do not hear the POP when I throw the switch.
The position of the fan chain does not appear to matter. Regardless of what speed the fan is running at (including off) the POP only occurs when all four lights are off.
Since there is no current flowing in the light portion of the unit with the light chain in the off postion, why would it pop when power is cut off?
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DerbyDad03 wrote: ...

It's not the lights portion that is "popping" apparently.
Take it down/apart and look for where the arcing has left marks--they'll be there somewhere.
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On Fri, 27 Jun 2008 04:56:27 -0700, DerbyDad03 wrote:

Remove the fixture and check for loose wires, arcing, dust. Blow out motor with compressor. It's amazing how much dust and grime accumulate over time. Keeping the motor dust free will let it run cooler.
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Franz Fripplfrappl
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On Fri, 27 Jun 2008 04:56:27 -0700, DerbyDad03 wrote:

Are the lights on a dimmer or timer or remote control built into the fan unit?
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DerbyDad03 wrote:

It does sound like something is not right in the motor or motor switch area, probably conductive tracking from 20 years of grime or vaporized switch contacts accumulating where it can cause trouble.
I'd recon that there may be a little current flowing through the motor windings even when the motor switch is OFF, and when the wall switch opens and breaks that current the inductive kick from the stored energy in the motor windings makes something arc enough to cause the noise the OP's hearing.
If two or more light bulbs are switched ON they will provide a damping load across the motor inductance and the "kick" won't reach a high enough voltage to make the arc occur.
Sounds like it's time for a teardown and inspection. The proximate fault may just be in the motor speed control switch itself, and not in the motor.
Jeff
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Jeffry Wisnia
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On Fri, 27 Jun 2008 13:46:52 -0400, Jeff Wisnia wrote:

sounds like some info is bad though. turning off a circuit only causes a pop when the circuit was NOT passing current. Stopping soething that is not going should not do anything. I think he needs more investiation.
CL
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