On New Year's Eve, I was cooking fillet steak for a party with some friends. I first put it in the pan to sear it and then in a hot oven for a few minutes to finish it. As I was pulling it out, a beeper in the oven control panel started screeching. As the steaks were done and there was nothing obviously wrong with the oven, I simply turned it off at the fuse box and went on to eat the steak and ring in the New Year. I switched the oven on again prior to going to bed, but about two hours later it started beeping. I crawled out of bed and switched it off.
In the morning light, I switched the oven on again. Sure enough, a couple of hours later, it started beeping and none of the buttons would quiet it. I deduced that if the beep started with a cold oven after a couple of hours then it was unlikely to be an over temperature alarm and was most probably a time out -- i.e., the timer had counted down to zero. I switched it on again to observe pre-beep performance.
This time I noticed that the clock button, which was a plastic sheet over contacts on the faceplate, did not set the clock mode but did activate the timer in the same manner as the timer button. Then I perceived a slight bump in the plastic over the clock button icon. At this point I could deduce that something, possibly to do with the bump, had somehow jammed the clock button and set the timer counting down.
I then removed the front panel of the control unit. The plastic sheet covering the front panel had a transparent area over a slot behind it, which was where the clock display was mounted. And the slot was just over the row of push buttons. Just at the edge, where the plastic covered the slot, I saw the dessicated cadavers of some tiny insects.
I shook those out, inverted the faceplate, banged it on the table, and for good measure, ran a piece of paper between the plastic and the faceplate. Several bits of exoskeleton showered out.
After reassembly, the oven worked perfectly, and I now know what debugging means!
This entry was submitted by Phil Hughes and edited by Lauren Muskett.
Phil Hughes is CEO of Clustered Systems Company Inc.
Tell us your experience in solving a knotty engineering problem. Send stories to Jennifer Campbell for Sherlock Ohms.
Thanks, jmiller. I forwarded that info to my husband for dealing with our oven--maybe. He works in the paint department of a hardware store. He says the controls for his paint mixers have gone from standard toggle switches (and pot dials) over to touch pads. Where once he could change out a switch, he is now "stuck with the infernal pads." The springs weaken, but worse, the electronics board on which they rest stared to flex backward over the years. When the first repair tech came through to deal with this problem, his "solution" to an inoperable pad was to cut a hole in the plastic which overlays the button to grant the switch more travel. Eventually, my husband says he glued little plastic bumpers to the buttons to be able to use them at all.
I will warn people because I'd hate for someone to try and fix something and not be able to get it back together. However, often if you can get the touch pad out of any machine and then take it apart you will find the plastic parts, springs etc. inside the machine and these can be modified to solve the issue. For instance if you are getting a stuck button error message you can shave off a little plastic to provide some clearance and prevent the stuck button. Be careful not to shave to much. You really can't glue plastic shavings back onto a spring. If there is a button that will not push you can use a peice of tape or a sticky note as a shim by placing it on the bck side of the touch pad. Just some of the tricks of the trade to get machines out the door when the parts aren't exactly what you ordered.
I'd love to be able to do that, in particular to get rid of car noises that tell me the door is open (duh) or the seatbelt isn't fastened (duh again since I'm OCD about that item). For PC noises, I've always just disabled the sound in the control panels. At least on the Mac you can easily do that, don't know about a Win machine.
On a related note, I have cut out the speaker on a few devices over the years. It started with removing the "pc speaker" some decades ago. Those were horrid when the PC would have issues.
jmiller, I remember being told exactly the same thing back in the 90s, but as a member of the press. What arrogance. Also, in many cases, how inaccurate. Also, thanks for the info about the touchpad. That's what my husband said. Of course, the answer is infuriating, because that means we can't fix it ourselves and basically, we've been given a poor design and told to live with it.
I agree about the beeping appliance volume control. However, I need to point out that annoying cell phone beeps have now been replaced by someone else's annoying idea of "music."
It's interesting how when you look underneath those touch pads it's just the same plastic pieces behind the membranes. Unfortunately, the mechanical spring has been removed and without a good ole metal spring the plastic just can't handle the lifetime load. I guess someone should have realized that plastic deforms when it gets a little warm and without a metal spring the buttons going to quit working.
I was actually told by one of these "marketing" people that the American consumer will like what we tell them to like. Therefore, they had the right to tell us what to make because the consumer would like it. Funny how often the consumer doesn't necessarily like what they are told to like.
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