About three weeks ago, I noticed that when I put my iMac to bed and turned off the ceiling fan, there was an audible "POP" from the external speakers attached to the Mac. Finally, my wife asked me when I was going to do something about it because, obviously, there is another bad wall switch. I think I've replaced ~six in the last 12 months. I'm sure they were the cheapest contractor grade and are beginning to show their age (~12 years) by simply decomposing!
There are two switches in this particular place, one for the fan and one for the fan lights. Since the fan lights switch wasn't causing any problem, I deduced that it must be the only other switch that was falling apart. You may notice my logical skills are improving with age!
So, I go buy a new 15 amp single-pole switch and start removing the old one.
Now, if you've ever watched an electrician wiring a house (or even replacing a switch, you'll remember that they absolutely detest using the normal screw terminals found on most switches and receptacles. Instead, they like to strip a half inch of insulation and stick the bare wire into little holes that have one-way friction/springs inside. That's much quicker than un-screwing the terminal and then tightening them. And 99% of the time, it works just fine. However, in this case, as soon as the "bad" switch was disconnected to the mounting box, the common wire going to the other switch popped right out of its hole! Part of the problem, OWO*. Naturally. I put the now freed wire on the screw terminal of its switch, no more lose wiring!
But not before noting that the reason the wire came free was that the plastic around that hole had cracked and the spring-friction holder no longer did its job. But the screw terminal still looked secure.
Next, I replaced the "bad" switch which displayed absolutely no external signs of failure.
I flipped the circuit breaker back on and turned on the fan. Now, I turned the fan OFF...still with a "POP!"
Could it be the other switch? I swapped the old "bad" one for the one that had a known but very minor problem. I re-powered the circuit and went through the ON/OFF routine. Yep, it still produced the "POP!"
The fan is as old as the switches, could it's never used speed selector/ON/OFF switch be the problem? It only costs a few dollars to find out (along with some fidgeting with the three globes and light bulbs...). And, the answer is?! Nope! Still getting the "POP." Plus, even though I removed the wires from the old switch and inserted it in the corresponding hole of the new one, we now have only a two-speed fan, instead of three speeds...oh well, it's not arcing (or even smoking! And we turn the thing ON/OFF with the wall switch, anyway).
Mind you, the light switch and the power circuit for the fan and the computer stuff are on two completely searate circuits. This made things even more confusing for me, anyway...unless there was possibly a grounding problem. I even powered the speaker off the UPS hat powered the Mac. Still no change.
Finally, I started rerouting the small jungle of wires behind the iMac (That's really the reason they make the monitor so wide, you know). Guess what!!! The induced noise was from two or more wires being too close to one another. Probably the cable from the iMac to the input of the speaker system. It is quite likely to be unshielded and was acting as an antenna, along with the other wiring back there. Cheapest fix I've ever done, clean up the wiring runs!
Oh yeah, about three weeks ago, I moved the transformer brick up on the desk and nearer most of those wires...
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Old
Wise
One
