Monday, April 20, 2015

Troubleshooting and Sherlock Ohms


Recently I found a blog at Design News magazine called Sherlock Ohms that has brief case histories about electrical troubleshooting and failure analysis of products. These cautionary stories teach you to be persistent and logical. You will enjoy reading them if you’re looking at writing a how-to speech about troubleshooting.










Sometimes it’s the normally reliable little stuff that makes a product fail. In their archives I found five cases just about fuses: The Failed Fuse Fooled Me, Always Inspect the Fuses, The Fuse Holders Wouldn’t Hold, Fuse Holder Follies, and Fuse Holder Mismatched to Fuse. The first one involved a fuse like the one containing a little wire (shown above) that visually looked OK, but actually had melted beneath a metal end cap rather than near the middle as usual. It was not really connected, which was easily confirmed by removing it from the holder and checking for electrical continuity.

Some fuse troubleshooting is much easier. One morning my brother-in-law got a rental truck for a move. As the sun began to go down he found that the headlights didn’t work. When he checked the fuse block he found there was no fuse for them. The dealer had apparently cannibalized it to fix another truck, but then forgot to get another one to replace it. Luckily he found an auto parts shop before the night got really dark.


















Those fuse stories reminded me of a pesky switch failure that once bedeviled my dad for most of a day. The picture on the 25” Heathkit color television set he’d built had blacked out. Most of the transistorized circuitry was on plug-in circuit modules. But, on the back of the chassis there was a little double-pole double throw (DPDT) slide switch similar to the one shown above. It changed the set from normal operation to a service position for converging the dot-matrix picture tube via a built-in dot generator.   

















Normally (as shown above) in Position 1 the center switch contacts connect to the pair on the left, and in Position 2 the center contacts connect to the others on the right. His switch had weak springs, so there also was an unexpected 3rd null position where the center contacts were not connected to either end. There was no control signal sent to turn on the high voltage power to the picture tube. Detailed troubleshooting instructions supplied with the set had considered the circuit modules but not a a bad switch.

Dad finally gave up, and we pulled the chassis, put it in the back of our station wagon, and drove to the local Heathkit dealer. Their technician first checked the expensive high voltage power supply module to see if it had failed. It was fine, so he tried wiggling the switch and found that it would only sometimes snap to either of the correct positions. A $0.25 component had disabled a $500 kit. 

Peculiar things also can happen when there are unintended connections, which are known as sneak circuits. There is a Sherlock Ohms case about a minivan with Solder blamed for faulty window operation. I also have heard of sneak circuits being created inside of dual-filament bulbs used for tail and brake lights on cars or trucks, when one filament eventually sags enough to touch the other. There also are metal whiskers that grow from electroplate, which are a whole other story.




















The funniest Sherlock Ohms I read was The Case of the Confused Customer. It involved an X10 control module similar to the one shown above that wouldn’t work because the customer didn’t take off the white plastic protective cover over the two prongs for the built-in AC plug. The instructions forgot to explicitly tell him he needed to do that before he could plug it in.  

The image of a fuse came from André Karwath and that of a DPDT switch came from Magnus Manske, both at Wikimedia Commons.

Sunday, April 19, 2015

Why I’m Better Than You is a very bad title for a speech

Today’s Pearls Before Swine comic featured a Conference of the Self-Righteous where four speakers began arguing because they all had used that same very bad title which just insults the audience. They instead should have used some variation on How You Can Be Better.

Thursday, April 16, 2015

Don’t be an acousmatic speaker!






















That’s when you manage to hide completely behind the lectern. Unless you are either George Bush or Hillary Clinton you won’t need to hide to avoid flying shoes. Acousmatic is a fancy jargon term you can use to amaze your friends. Wikipedia says that:

“Acousmatic sound is sound one hears without seeing an originating cause. The word acousmatic, from the French acousmatique, is derived from the Greek word akousmatikoi (ἀκουσματικοί), a term used to refer to probationary pupils of the philosopher Pythagoras who, so that they might better concentrate on his teachings, were required to sit in absolute silence while listening to their teacher deliver his lecture from behind a veil or screen.”

If you hide like that, then your audience can’t see your gestures and you have no eye contact with them. That will make your presentation relatively ineffective.

Last year Brian Kane published a book titled Sound Unseen: Acousmatic Sound in Theory and Practice. Langdon Morrison reviewed it at Music Theory Online. In points [7] and [8] he notes that the Pythagorean veil really may have just been an allegory. Kane states the history for the key myth in a paragraph on page 50 of his book:

“The term ‘acousmatic’ refers to the disciples of Pythagoras who heard the philosopher lecture from behind a screen, curtain, partition, or veil (M1, M2b, M3, M4, M5, M6, M7, M8, M9, M10). The reason they remained on the far side of the veil was to promote a form of concentrated listening (M2a, M8b) or to emphasize the master’s message (M1, M3, M6, M7, M9) undistracted by the visual aspects or physical presence of the speaker (M1, M3, M6, M7, M8, M9). In addition to keeping a vow of silence for five years (M1, M5, M6, M7, M10), this exoteric ritual formed part of an initiation into the Pythagorean school where pupils would then see the master (M1, M5, M6). From the experience of the acousmatics, we derive the adjectival sense of the term, meaning a sound that one hears without seeing or being able to identify the originating source (M2a, M2c, M3, M4, M6, M7, M8a, M8b, M10, M11a). The term was transmitted by Diderot in the Encyclopédie (M1, M5) and in the pages of Larousse (M6, M10). A related term, ‘acousmate’ (M1, M3, M11), was found in the Dictionnaire of the Académie française (M11b), as well as Larousse (M3). Apollinaire, a lover of rare words, used ‘acousmate’ as the title of two short poems (M1, M11b). These poems tell of voices heard in the air (M1, M11b). The writer Jérôme Peignot was the first to employ ‘acousmatic’ as a term for describing musique concrète (M2c, M3). Schaeffer learned about the term from Peignot (M1) and, by attaching it to the phenomenological epoché, developed a concept of acousmatics that formed a significant part of this theory in the Traité (M2d). Modern audio technology preserves the ancient acousmatic tradition of the Pythagorean veil (M10) or its mystical variants (M11). Acousmatic music continues the tradition of musique concrète Pythagoreanism by veiling sounds, through the use of the loudspeaker, of all causal and contextual associations (M2a, M4, M8b). “

The image was created by combining a face and a lectern found at Openclipart.



Tuesday, April 14, 2015

Ruination Day




















According to singer-songwriter Gillian Welch, today is Ruination Day because of three horrible events:

1.)   The assassination of Abraham Lincoln in 1865

2.)   The RMS Titanic hitting an iceberg in 1912 & sinking

3.)   The Black Sunday dust storm in 1935.


On her 2001 album Time (The Revelator) she mentions them in two songs you can listen to at YouTube - April the 14th Part I and Ruination Day Part II. Part I ends with:

“....Ruination Day and the sky was red.
I went back to work, and back to bed.
And the iceberg broke, and the Okies fled,
And the Great Emancipator took a bullet in the back of the head.”


Gillian Welch, Emmylou Harris, and Alison Kraus also were the voices of The Sirens in the movie O Brother, Where Art Thou? 

On a happier note, today we also celebrate the birthdays of country singer-songwriter Loretta Lynn (1932), baseball player Pete Rose (1941), and actress Sarah Michelle Gellar (1977).

An image by Carol M. Highsmith of the statue in the Lincoln Memorial came from the Library of Congress.

Monday, April 13, 2015

What’s worse than being the boy who cried wolf? It’s being the girl who cried goldfish!




















The cover of Sam Horn’s new book Got Your Attention? (How to Create Intrigue and Connect with Anyone) has an image of a goldfish below the title. It goes with two sentences in the introduction:

“Did you know goldfish, yes, goldfish, have longer attention spans than we humans do?
 

Nine seconds to our eight. At least that’s what Harvard Business School researcher Nancy F. Koehn reported in a February 2014 Marketplace Business article (ref 1).”

She also has a blog post titled Did You Know GOLDFISH have Longer Attention Spans Than Humans Do? in which she crows about how the goldfish is becoming the “poster fish” of our allegedly shrinking attention span.

But, neither Sam nor Nancy checked carefully to see where that dubious pair of statistics really came from. It’s a web page at a silly website called Statistic Brain. Last December I blogged about how Statistic Brain is just a statistical medicine show, and included the attention span statistics as my second example. 

 That’s too bad, since both the book and her TEDxBethesdaWomen talk on Intrigue make some interesting points.

Friday, April 10, 2015

How many American adults have impulsive anger issues and access to guns?
























A press release from Duke University on April 8th stated that:

“An estimated 9 percent of adults in the U.S. have a history of impulsive, angry behavior and have access to guns, according to a study published this month in Behavioral Sciences and the Law. The study also found that an estimated 1.5 percent of adults report impulsive anger and carry firearms outside their homes.

....The researchers analyzed data from 5,563 face-to-face interviews conducted in the National Comorbidity Study Replication (NCS-R), a nationally representative survey of mental disorders in the U.S. led by Harvard in the early 2000s.


The study found little overlap between participants with serious mental illnesses and those with a history of impulsive, angry behavior and access to guns.
 

‘Gun violence and serious mental illness are two very important but distinct public health issues that intersect only at their edges,’ Swanson said.”

Several of my blog posts have discussed another magazine article on social fears based on data from the NCS-R. Those large, careful surveys continue to provide us with lots of useful information.  

The ancestor of Yosemite Sam was adapted from an 1898 Puck magazine cartoon

Tuesday, April 7, 2015

Carpet cleaning, with just a little lye











For the past year or so I’ve been hearing radio ads from the local franchisee of a firm called Zerorez. The description on their web site said that they clean using something magical called Empowered Water (a trademark), and that their process leaves zero residue - which is why the company name is a palindrome. That’s amazing and somewhat misleading marketing jargon. Watch a brief video from their Albuquerque franchisee.
















So, just how do you really make empowered water? Is it like Rock Water? Or, do you send it to visit a sweat lodge in Sedona?  Actually, as shown above, they just add add some sodium chloride (salt) to the water, and apply a direct current to produce a solution containing sodium hydroxide (lye, or caustic soda). The folks at EAU Technologies who supply the equipment to Zerorez grandly refer to that liquid as Primacide B Empowered Water. When I checked at the web site for the U.S. Patent and Trademark Office, I found that EAU Technologies had abandoned their trademark for Empowered Water as of January 5, 2015, so its status now is listed as DEAD. What they are doing is not startlingly new, just a scaled down version similar to the old familiar chlorakali process

Zerorez does have U. S. patent ##6,638,364 for their cleaning process. Its title is a lot more descriptive than their marketing mumbo jumbo - System to clean and disinfect carpets, fabrics, and hard surfaces using electrolyzed alkaline water produced from a solution of NaCl.















Does their process leave zero residue? That would require a perfect rinse, so I doubt it really does. But, as shown above, any sodium hydroxide residue left in the carpet eventually would react with carbon dioxide in the air, and form harmless sodium bicarbonate (baking soda).