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Opinions of a Contrary Dinosaur.
The Durability of Electronic Circuit Boards in Appliances.
 


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Opinions of a Contrary Dinosaur . . .

           In this ever more computerized world, some people (especially my kids) consider me to be the last surviving dinosaur. You see, I still prefer to buy appliances with old-fashioned dial controls and electro-mechanical 'pinwheel' timers. This contrarian bent is not out of character for me. I believe in KISS (Keep It Simple, Stupid).
          Much to the chagrin of my teen age daughters, I will purchase an automobile only with a standard transmission, crank windows and a simple radio. Furthermore, this contrary dinosaur would also like to see Daylight Savings Time abolished, suspects all professional sports are fixed and thinks that someone forgot the 'C' in RAP.
          In modern life, we are surrounded by electronic circuit boards performing a myriad of functions; all alleging to make our lives more convenient. Everything from coffeepots to washers, from televisions to telephones, from the security monitor on the wall to the thermostat in the hall; all depend on an electronic circuit boards to operate. I remain unimpressed by appliances sporting the latest touch pad electronic controls with memory functions and LCD displays. I wonder what on earth would a clothes washer ever need to remember?  Why would my dryer need to know what day it is?   What information could my dishwasher possibly tell me that is so urgent that I would need to be updated every time I entered the kitchen?
           Doesn't everyone INSTINCTLY know that electronic circuit boards are susceptible to heat and static discharges as well as wet conditions or humidity?   Instinct: that feeling of sadness surrounding you as you watch air bubbles rising from your brand new digital temperature tester laying at the bottom of the swimming pool.  Instinct: that sinking feeling when you smell smoke emanating from your digital multimeter.  Instinct: the lump in your throat when you power up a new circuit board for the first time and all it does is make snapping noises.
          I remember the first time I truly appreciated that electronics and water don't mix. As a young newlywed couple, my new wife and I decorated our first apartment by putting a beautiful fern on top of the TV set. All was well until the day the fern needed a little water. The fern's potting soil was quite dry. So, the water quickly drained straight through the pot into the TV set. As the water found its way across the picture tube to the high-voltage rectifiers, a series of small explosions and lightning bolts emanated from the back of the set. Before we could unplug the TV, there was a final eruption accompanied by flames shooting from all sides. No one was hurt. There was no permanent damage to the apartment except for the TV, which ended its existence as a smoking charred puddle of glass and plastic beneath a fried fern.
           Did you know that manufacturers are so concerned about static electricity that they ship replacement boards in special antistatic bags? Appliance manufacturers strongly urge repair technicians to wear ground straps on their wrists or special gloves when it is time to take the electronic circuit board out of the antistatic bag. This is to prevent static electricity built-up (from such sources as shoes on carpet or the movement of the technician's clothing) from being transmitted to the circuit board . Most appliance manufacturers recommend handling replacement electronic circuit boards by the edges to prevent fingerprints on the etched surfaces.
           I shake my head whenever I receive a replacement board or module to repair an appliance. The shipping carton often carries numerous warnings: Fragile! Store in a Cool, Dry Place! Do Not Stack! Open Only In Accordance With Manufacturers Recommendations! It is not what I would consider 'KISS' to design a household appliance which requires AS AN INTEGRAL PART something so fragile that it must be handled with gloves and static straps. That ANY appliance circuit board works AT ALL for ANY amount of time is nothing short of amazing to me.
           I begrudgingly own a microwave oven with a electronic circuit board. It is getting increasing difficult to buy a microwave without a electronic circuit board. The electronic circuit boards on microwaves seem to be fairly durable; their weakest point being their susceptibility to power surges. And, with prices of microwave ovens being so low, durability is not a large concern anymore.
           I would only own a clothes washer or a dishwasher with a mechanical dial timer and old-fashioned switches. I think putting a electronic circuit board or touch-pad timer in such an appliance is asking the board to work in a wet, humid environment while subjecting it to heat, moisture and vibration. That's a bad idea in my book. I first saw my first electronic circuit board in a washing machine in the early 80's. At first, the failure rate was excessive. They were a warranty-repair-man's dream because they would sometimes only work for a month. Over the years, durability improved. But, in my experience, the life span of a washing machine electronic timer is less than half of a mechanical timer and about 50 percent more expensive.
           I would never buy a refrigerator with any sort of electronic gadgetry. When a refrigerator compressor starts, it pulls a huge current for a short time. Perhaps you might have been in a house and noticed the lights dim slightly when the refrigerator started to run. That is an indication of how much current even a small refrigeration compressor needs to start. Those frequent moments of uneven power can play havoc with electronic circuits.
           Ovens and ranges usually have some sort of clock as standard equipment. The timed oven is a convenience for preparing dishes and a necessity for self-cleaning ovens. In my experience, oven clocks are a weak link in the oven circuitry. As a group, oven clocks rank third behind terminal blocks and elements as the oven repair part I have replaced most often. That's because they are made cheaply. A durable industrial or commercial timer capable of switching a 240 volt, 20 amp load accurately and reliably could easily cost more than what a consumer would want to pay for a whole range. So, appliance manufacturers opt for a lightweight timer to keep the sales price down. I won't buy a range with an electronic touch-pad timer and I won't buy a self -cleaning oven. My experience is that electronic touch-pad oven timers are just not as durable as old-fashioned oven clocks and very expensive to replace. And, if you don't have a self cleaner, you don't need the clock at all.   (KISS !)
           Those are the opinions of a grumpy old contrary dinosaur. I guess I will always prefer appliances controlled by old-fashioned dial controls and electro-mechanical 'pinwheel' timers. I distrust the durability of electronic circuit boards. I question the added value of lights, displays and gadgetry to the ultimate usefulness of any appliance.

          And electro-mechanical controls don't BEEP at me!   But that is another story . . .

03.10.12






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