Introduction: Trouble Shooting an Old 3-setting Dual Electric Fan Problem
As requested by a member, I am outlining the steps I took to fix a dual window fan I had set up in my "computer room" at home, that had worked all last summer. But this year, when it was plugged in, it didn't work at all. Mistakes are included and explained so you don't make the same ones.
Before just blindly looking for problems, I thought it through some.
#1: could a motor be burnt out?
Answer: not likely. It had not been run all winter long. Dust may have accumulated inside of it, but it should at least spark, smoke, hum or do "SOMETHING". This did nothing.
#2: how about the cord?
Answer: possibly, but again, since there had been no tension nor stress on the cord all winter, having been stored away, it wasn't much more likely then the motor.
#3: how about the switch?
Answer: the switch was a four position (off, left fan on, right fan on, both fans on) old mechanical switch encased in Bakelite (which tells some of the older members here just HOW old it is :-) And, I remember it giving a visible flash or spark visible around the seam when the fan was switched on in the dark. Sounds like a good starting place.
Step 1: The Switch
I disassembled the switch and found nothing "remarkable". No broken wires, no overly carbonized contacts. While open, I cleaned the contacts, since they were now completely exposed gingerly, so as not to wear them down and make any gaps even worse.
Step 2: The Cord
Since I had to switch open, I tested the cord that runs TO the switch. As I mentioned in my forum posts, I got what I at first thought were confusing results.
One side of the line switched on and off just fine. The other side did not, but then, I assumed only one side ran through the switch (which it did) and that the other side would not show continuity. But then, I got a reading that the other side did not work, but then did again. I assumed (wrongly) that, with the position plate off, I didn't remember which position was off, and I put the switch back together.
This is the mistake that made me spend an extra 20 minutes on a job that should have ended right there.
Step 3: The Motors
I then disassembled the cage around the motors and the back case to expose the coils. Now only were they pretty much in pristine shape, but fairly free of dust and with no smell or evidence of sparking (carbon trails), etc. I could have tested the motors with a direct connection to power, but didn't feel confident enough at this point.
This put me in a quandary. So I revisited the steps.
#1: I dismiss outright, as there is no problem with the switch
#2: I do have that one taped area where I added a cord years ago.....best check it....
Step 4: Back to the Cord
Had I done this when I was working with testing the cord the first time, I would have saved myself a lot of time.
Unwrapping the electrical tape, the wires literally fell apart. Apparently, I had "fixed" this back during a period of time when I didn't have a soldering iron and I had "temporarily" braided the wires together, and then forgotten about it (not a good idea, btw). The moving of the fan about eventually loosened the wires enough to allow them to spark, and carbonize and lose their "grip" on one another. They eventually partially slipped apart and partially broke.
So, I cut, restripped them, and soldered (this time) the two wires together, REMEMBERING to FIRST put a piece of heat shrink tubing in line, so as to not have to use electrical tape. Hitting that for a bit with a heat gun (fancy hair drier), and it was sealed and ready to roll (or become a fan of mine again *chuckle* Sorry, I couldn't resist the pun. :-)
You might call this a Cool(ing) project.....ok, I'll stop now.