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Sherlock Ohms

Case of the Fried Solar Heater Controller

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Rob Spiegel
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Re: Just throw it away???
Rob Spiegel   4/11/2012 1:24:46 PM
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Sounds like the documentation saved you. How it is with the new compressor? A lot better whiel consuming less energy, I would imagine.

bobl
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Iron
Re: Just throw it away???
bobl   4/11/2012 12:54:45 PM
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In this case, my electric bill went from about $50 to $200 in a month.  Yes, I was able to show that the unit would run for hours and not cool down the apartment.  The weather wasn't even very warm yet.  The most telling chart was when it tried to cool down the apartment from 74 to 70 degrees in the evening when the outside temperature was lower than 70.  Yes, I could have opened a window, but that would have defeated the reason for all the monitoring.  It took 6 hours (6pm to midnight) to cool it that day, all duly noted.

 

Unrefutable documentation is the way to go.  He really couldn't argue with the numbers.

Rob Spiegel
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Re: Just throw it away???
Rob Spiegel   4/11/2012 12:19:33 PM
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Good for your for documenting the problem, Bobl. Do you think that made the difference in getting the new compressor? Perhaps if you hadn't documented it, you wouldn't have been taken seriously.

bobl
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Re: Just throw it away???
bobl   4/11/2012 11:46:24 AM
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My theory on this subject is.

 

What's the worst that can happen?  If I take it apart and can't fix it after spending a few hours/minutes, what have I lost?  Just the time.  I may have just saved me a lot of money fixing something instead of replacing it.

When something breaks/stops working, I always look at it with the intention of at least trying to find an obvious problem.  Blown fuse, etc.

 

I had a problem with my apartment A/C running and not cooling sufficiently.  I borrowed an Agilent datalogger from work, along with a number of thermocuples.  I monitored the temperatures in and out of the FAU, logged the compressor on signal.  I was able to show that it wan't cooling properly.  The head maintenance tech complimented me on the charts that I showed him the demonstrated the lack of performance.  "You've done your homework".  Ended up with a new compressor out of the deal.

Rob Spiegel
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Blogger
Re: Just throw it away???
Rob Spiegel   4/10/2012 12:31:14 PM
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I know exactly what you're talking about , John. My daughter has a desktop CD player with a lid that won't stay closed. She thought she needed a new one. I gave her a rock to set on top of the lid.

johnr
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Iron
Re: Just throw it away???
johnr   4/9/2012 3:41:45 PM
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Rob,

Don't get me started on the stuff I've had to send to the landfill because it couln't be repaired!  I've sent probably a dozen of my kid's CD players to electronic recycling (not the landfill, fortunately) all for the exact same reason:  there was a tiny plastic tab that held the clamshell case closed and that tab broke off.  Usually it was lost forever, but even if I had it I couldn't find a glue that would make a permanent repair. Everything else in the player would work fine, but the lid wouldn't stay closed.

While saving up for a new one my daughter did her own temporary fix:  a big rubber band to hold the lid closed. Not pretty, but it worked.

Eventually the solved the problem of breaking CD players permanently:  they got iPods.

johnr
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Iron
Re: Just throw it away???
johnr   4/9/2012 3:34:55 PM
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Good point, but I don't have billable hours so I don't explicitly earn more for spending a couple hours more at work as opposed to fixing something myself. Working extra might lead to more money when it salary evaluation time if my extra work results in doing something useful that gets recognized by management, but that's not a given.

Plus, there is something intensely satisfying about fixing something, or even just knowing you could if you had to.  I recently helped my daughter experience that when I walked her through how to re-light the pilot light in the furnace in her apartment one cold evening this past winter.  Otherwise she would have had to wait until the next morning when the maintenance people showed up.  She said it felt really good not to have to depend on them any more!

Plus I really enjoy it.  I work all day on a computer; when I leave at the end of the day there's nothing to point at and say:  "I made that today".  I just push bits around on a hard disk somewhere, so working with my hands is a kind of therapy. Now I know that's cheaper than seeing a therapist!

cvandewater
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Gold
Re: Just throw it away???
cvandewater   4/9/2012 3:28:45 PM
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Jack,

Thus continues the cycle of throw-away, by looking only at the cost and not recognising the value of being able to understand the operation of and fix the product yourself - which is a great motivator and pride factor, too often misunderstood - as well as the value of not adding to the waste stream.

Another factor often not considered is that people will not spend a few minutes to fix something because they consider it not worth their time, only to take hours and drive all over town to shop for the replacement. How crazy is that?

One totally ridiculous part of American culture seems to be to spend several hours every month or so, either to have the oil in the car changed (which apparently is done unnecessarily every 3k miles) or to go to the tire center to have a rotation. Each of those visits includes time to make an appointment, go to the center at the scheduled time; have a friend pick you up again or sit in a non-descript waiting room for around an hour; if required pay for the unnecessary service and drive home again. Each instance costs you anywhere up to two hours and when asked, everyone will give you their version of why they have no time or not want the hassle of changing oil or rotating tires - while you can do that at home in about 15 mins: you save time, you save money and you *know* that the work is done. How is that more hassle than wasting 2 hours, hoping that the work was done and paying for the experience?

I know - fixing a tricky appliance can involve a lot of time, possibly result in a still-not-working device and other frustrations, but the times that you can get it to work and often, by understanding how it works, actually make it better, is priceless experience in my opinion.

BTW, if you have time to answer (or even read) this post then you don't value your spare time that high.... ;-)

johnr
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Iron
Re: Company
johnr   4/9/2012 3:15:46 PM
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Well, I did the work at lunch, so no loss there.  The company was founded by a bunch of ex-HP engineers, so they encouraged use of lab stock for private projects (within reason, of course) as had been the practice at HP back in the day.  It's amazing what you can learn (that they don't cover in college classes) by fooling around with stuff!

Later on, several of us built Z80-based CP/M computers with parts from lab stock, with the company's blessing. We learned a lot about firmware (from fiddling with the BIOS) and microprocessor-based design from that project that we leveraged into user interface and feedback control systems in our products.  In one example, I used that experience to design and build a Z80-based test set for testing the image processing boards in the system.  The company bought a lot of experience for its engineering staff with a couple hundred dollars of lab stock parts!

I'm still encouraged when companies like Google encourage employees to work part time on similar projets.  It's nice to see G-job culture live on!

johnr
User Rank
Iron
Re: Keep it simple
johnr   4/9/2012 2:57:29 PM
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Sounds very similar to the system I fixed.  I think there may have been one other logic circuit that would run the pump if the temperature in the collector got too close to freezing.  I don't recall (or didn't notice) anything that would drain the water out of the collector to prevent freezing, so heating up the collector during the very rare occasions when temperatures got very low (this was in Phoenix, after all!) seemed like a reasonable compromise, I guess.

Of course, this was all 30+ years ago, so my memory of some details has suffered "bit rot" over the years!

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