Breaking the epoxy bond under SMD ?

SOT223 package.

Full spec dissipation requires 4 square inches of copper under the device. Lower dissipation specs with less of a heat sink. The back is the device is plastic. Most of the heat comes out the large solder tab. There is a 1.6mm air gap under the plastic case to deal with glues and to insure that the tab mechanically hits the copper head sink area. There is almost no value in obtaining a thermal connection to the epoxy case, so there would be no benefit to using a thermally conductive epoxy glue.

Epoxy does not "clear away" when hit with a soldering iron. What it does is crumble and burn leaving a charred mess. The heat conductive variety will conduct enough heat to the PCB to also char the PCB. I agree that if it didn't reek when you hit it with the soldering iron, it's probably not cyanoacrylate adhesive. That leaves hot melt adhesives and various acrylic glues. If it seemed to melt away at a very low temperature, it's probably hot melt. If it took some effort, and it simultaneously melted and charred slightly, it's acrylic.

Please specify what you mean by the "manner of epoxy"? Melt, char, crumble, volatize, explode, etc?

As ever, you've lost me there. Whether you were referring to the whole post - which is what it read like from where I was sitting - or just the preceding bit of text as you claim, I still don't get what you're trying to guess about. If you're having to guess at anything, presumably, you don't understand, and then cryptically, you say that you understood exactly. It all seemed perfectly clear to me, and apparently, everyone else ??

Arfa

Yeah, everyone else got it. I understand why you misunderstood -- you misread the context of the last statement.

I might say to all the professionals in this group -- how can you work and respond to postings at the same time?

Crumble without clumping or sticking and without a change of colour and no observed smell given off.

Well William, I expect that's for us to know, and you to "guess" at ... :-)

Arfa

I'm currently editing articles for "Electronic Design". The writing quality varies from barely acceptable to horrible. I have to guess at a lot of things -- such as what the writer /thought/ he was writing about, or what a particular sentence Really Means. I often refer to Wikipedia or search the Web, but sometimes it's a guessing game.

Do any of you know what an IBC is? I didn't, and couldn't find the answer anywhere.

Intercontinental buttered crumpet

Ron

My compliments. I read the printed edition and find the articles to generally quite acceptable.

It's about the same everywhere, including usenet. The problem seems to be lack of time, not lack of writing abilities. Most articles are written to a deadline and look rushed. Often, the author doesn't seem to care, as in product releases and promotional literature. Other times, the author is so familiar with his subject, that he assumes that the reader is also similarly familiar and leaves things out, such as internal company acronyms. English as 2nd language authors tend to directly transplant foreign language constructs into the article, making reading difficult. Some people write exactly like they talk, which creates a difficult to read article. The various publications care more about advertising space than content, so articles get butchered in order to make space. I've scribbled a few articles in the distant past. I could almost recognize my original article buried in the published version. However, those are minor compared to what the magazines do to themselves. Authors are told to "not worry about style" and just supply the facts and details. The magazine editors will take care of making the article presentable. Permit me to offer some praise and sympathy.

If only they would pay my time, to write the docs in verse and rhyme.

Insulated Bridge Clip. They're used on Type 66 telephone blocks. They're usually bright red and indicate either a "protected" circuit or one that can't be detected with a common butt-in.

Like this, but covered with red vinyl insulation:

Thank you. Did you like "Did you buffer the buffered buffer?". That was one of my edits.

I'm not the only editor, of course. They have full-time writers and editors who do a very good job.

That suggests the original had significant problems. (I don't /know/, of course.) I have carte blanche to completely rewrite articles if I think it necessary. Many go through an extremely heavy edit -- and sometimes major rearrangement -- which the authors generally tolerate. (I would /like/ to think they look at the edited piece and accept it as a significant improvement. The late Bob Pease didn't. He told me my edits didn't contribute anything. That's about what Beethoven said about Haydn.)

In some cases I'm asked not to disturb the original style too much. I just finished editing a piece about the advantages of custom analog ASICs, for the purpose of not only cutting costs, but avoiding counterfeit devices. The author had a fun, engaging style, which I didn't have to alter in the process of cleaning up his writing (mostly correcting grammar errors and tersifying here and there). Indeed, my edits actually pushed the piece /closer/ to the original style.

There are articles so bad I feel my skull is about to explode. (In one case, the article was so awful and required so much time that I asked for a bit extra, which I got.) But I keep telling myself that, if engineers could write, I wouldn't have this job.

That's not it. Not anything like it. Though it /is/ used in telecom systems, on the block diagram an IBC is some type of regulator/isolator.

I haven't read it yet. I get my paper magazines 2nd hand, usually after a 3-6 month delay. I'll get to it eventually.

Does Penton seperate the technical editing from the grammar/spelling/style/fit editing? I had quite a problem with that when doing several book edits.

Maybe, although you'll never get me to admit that my work was lousy. I think (not sure) that my problem was my article trampled on the illusions of some of the magazine advertisers. While the advert and copy groups are not even suppose to talk to each other, I noted that most of the outright deletions were in this class. Also, there were at least three different editors involved, each with their own agenda and preferences, which may have contributed. Oddly, I left a red herring (intentional error) in the copy, which made its way through to the print version.

Do the original authors even see the results of all this editing? I didn't see anything until the final print version. However, times may have changed.

If Bob Pease's column in EDN were any indication of his writing skills, I would ignore his comments. It's a great collection of disconnected anecdotes and trivia, but would not pass for much beyond a grade skool paper. What editors do is make the content more accessible to a wider range of audience. It's very difficult to write something that is acceptable to both the experts and beginners in a field. I like to read magazines about things I know little. Little is over my head, but much is sufficiently esoteric to suggest that the author is only addressing those with equal expertise. What the magazine suggests is for authors to write to a reader that is an expert in his particular field, but not necessarily an expert in the article's topic. That works well.

Nice. However, I suspect that was written by someone involved in the marketing or sales of ASIC's and not an engineer involved in design or production.

True. Now, if you want to see really awful tech writing, I suggest you look at original (un-edited) patent applications and original business plans. I used to review these prior to application to the USPTO and vulture capitalists. One would think that something this important would deserve some careful editing, but that wasn't what I saw. I've been told that first drafts of legislation has the same problem, but I've never seen any.

A little context is always helpful. Next guess is "Intermediate Bus Converter".

Please send my consulting fee to the address below.

Not as far as I know. But my boss was surprised at how heavily I edited one piece, as it had been past another editor previously.

Apparently they do. One didn't understand why I had so heavily edited his work, and I had to justify it. The article was published as I had edited it.

Bob's writing was readable and understandable, but it certainly isn't what I would consider first-rate technical writing.

Bingo! I was just saying that to my boss. You want to write so that people who are simply /curious/ about the material can read and understand it. That's exactly what I do. Poorly written jargon discourages readership -- and thus subscribership.

No, he's a major engineer of such. His name is Frosthold, and I wanted to add this to his bio: "He has two brothers, Fasoldt and Fafner Frosthold, who design and build custom homes."

That's it! Thanks! (I'll get my boss to add a cross-reference.)

By the way, it's rather wordy. It could stand another editing pass.

PS: I'm typing this on a Unicomp buckling-spring keyboard. It's the only way to type.

One of the exercises that I survived in college was to reduce a technical article down to its basics by either removing words or rewriting them with a shorter equivalent. I became rather adept at this exercise and later introduced various prospective tech writers to the concept. It's often amazing how much verbage can be surgically extracted from an article without affecting the meaning.

Bah... I constantly switch computah keyboards when I work on multiple machines in my office, and when I use various machines at customers locations. As long as the general layout is similar, it only takes me a few seconds to adapt to a new keyboard. These vary from glass touch screens (Android, iPad, etc), elastometric flat (industrial controller), rubberized (restaurant kitchen), almost flat with minimal travel (laptop), dome keys (cheap keyboard), X shaped wire (better laptop keyboards), and antique teletype machines (brute force finger exerciser). Keyboards that give me problems are laptops where the keyboard layout is rearranged to provide room for the add keys which are never used, and Apple "chiclet" keyboards, which jam on the sides of the keys when dirty. If you're stuck on one keyboard style, I suggest you try some others. You might learn to like them better.

way to type.

I learned to type in high school on an Olympia manual. I typed at home on a Smith-Corona electric. Both have excellent, though quite different, keyboards.

In 1980, I was introduced to the pleasures of an IBM buckling-spring keyboard. That was it. In the intervening 30+ years, nothing has ever come remotely close. Tens of thousands of male typists will agree. It is in a class by itself.

About the same. I learned typing in Jr High Skool. I had a Smith-Corona electric portable, and used various others, including an IBM something with it's bucking spring and clattering keys:

I'll admit that I rather liked the way these keyboards worked. However, I can go faster and type longer with current generations of low-travel keyboards. I also didn't like the noise from the buckling spring keyboards.

Don't forget the various mechanical teletype machines. A Model 33 was standard issue for early time share and minicomputah i/o.

Yeah, there nothing like 70 grams of force and 6 mm of travel for the Model M, as opposed to about 20 grams and 2 mm of travel for todays keyboard. Try a glass keyboard (iPad) with about 3 grams of force and zero travel. Real men don't use wimpy keyboards.

Drivel: I play piano and synthesizer. It's much the same as computah keyboards. The piano/organ/synthesizer keyboards all look similar, but it doesn't take much in the way of tiny differences in key size and key action to foul me up. It takes me a few minutes of fumbling to get used to a new keyboard.

As Captain Redbeard Rum (Tom Baker) says in the "Potato" episode of "The Black Adder" -- "You have a woman's hands!"

Absolutely. For most men, a short-stroke keyboad -- the IBM's Selectric being the notorious example -- is anathema. (It took 20 years of random exposure to the Selectric for me to gain some degree of comfort with it.)

The Smith-Corona electric portables had a similarly long stroke that appealed to make typists. When Consumer Reports tested typewriters 50 years ago (I'm old, I'm old!), the panel strongly preferred the Olympia manual and the Smith-Corona electric portable -- my preferences, exactly.

For those out there wondering what this is all about... The preference for the IBM Model M and its ilk among male typists is /almost/ universal. It is "Das Klavier". I used to work with Charles Frankston (Bob's brother) who was also an M freak. He had a drawer full of them, and would sometimes wave one in my face: "Look what I have, and you don't!"

A short, easy throw does not a good keyboard make. The Model M's long stroke and non-linear relationship between force and displacement provide mechanical feedback that makes it posible to type faster and with fewer errors. Most users notice this immediately.

I don't play a musical instrument. But I once compared a Steinway with the Baldwin SD-10. The keyboard action was completely different. This might have been what ultimately drove Baldwin out of business.

Look at the trend in input devices. Pad computahs and cell phones are driving the glass keyboard market. Meanwhile, Apple is pushing style over function, producing unrepairable keyboards that look good, but are difficult to use. There are even laptops with glass keyboards.

I beg to differ. My definition is a bit different. I prefer anything that has tactile feedback, which means that the pressure required is lowered after passing a threshold. I also want a self centering key top and a non-jamming key travel. I don't care how far my fingers need to move in order to achieve this. Less travel is fine.

I haven't noticed. Back in the stone age of PC's, I purchased a Northgate keyboard for about $150 in about 1990. It was hailed as the ultimate typists keyboard by the magazines. Some of my customers also bought them.

The mechanism is basically the same as the Model M. I hated it. I'm not a speedy typist (about 40 mistakes per minute) but this keyboard made my typing worse. I finally gave up, sold the keyboard, and switched to the cheap plastic clones, some of which worked just fine.

There was considerable conglomeration in the piano biz. Samick is one of the biggies, which has bought many of the smaller brands (including about 1/3 of Steinway). A clue might be the cost of a good concert piano is about the same as a new SUV. Sales are also declining for mechanical pianos:

I learned to play on a Knabe (now part of Samick) baby grand. The action was very slow and required considerable force. It was great for practice because if I could play on the Knabe, I could play on anything. One of my customers has a fairly new Steinway. It has a rather heavy action, which I find difficult to play. However, it also is the best sounding piano I've ever heard, which more than compensates for the heavy action.

My standard price for a computah service call usually includes 30 minutes of me banging on the Steinway.

Eventually, I discovered keyboard synthesizers. The actions varied radically, ranging from extremely light, to heavy simulated piano actions. I bought a Korg DSS-1, which was one of the lighter actions. I can play about 1/3 faster (timed chromatic scale over 4 octaves) and play better on the Korg as I can on a regular piano.

Heavy piano keyboard actions have their place, but they're not superior or required. Same with computah keyboards.

Unfortunately, I think that the skill levels of many editors, don't match those which you seem to possess. I think that many believe that just because an article has been passed to them for 'editing', it must then be altered and generally 'messed about' in order to justify the fact that it *has* been passed to them, and that they have earned their fee. I have had articles that I've written, totally mauled by an insensitive hand. Words and phrases that I've chosen very carefully have been changed or removed, resulting in (sometimes) a complete reversal of the intention of a whole paragraph, let alone a sentence, indicating that the editor had no understanding of the subject material, nor the people who were its targeted readers.

I have also had grammatically correct structures changed into ones that are not, and correct spellings changed for wrong ones. By the same token, I became very close to the editor of one magazine that I wrote for, and he told me that my copy was a pleasure for him to work with, because the only 'editing' that he ever had to do to it, was an occasional slight precis-ing of a paragraph to make the article fit the space available. This was always done very carefully and sensitively so as to impact on the content as little as possible.

I think that one of the main problems with the publishing industry in this regard, is that these days editors tend to be self-employed contractors who find themselves editing a great deal of very varied subject material, so have to employ the same basic 'one size fits all' techniques to those works, and that's where it can go wrong. In days gone by, an editor was an employee of the magazine, and usually had a deep understanding of both the subject matter and the people who would be reading it.

As a slight aside, you mention that some people write as they speak. Some of the best technical publications that I have read, have been written in this style. One that springs to mind was a booklet on repairing Bally pinball tables, written by one of Bally's in house service team. It was written exactly as one engineer would talk to another, and was both amusing and practical. A perfect joy to read.

Arfa

Awww. And there was me thinking that link was gonna lead to somewhere we could see you playing some bouncy ragtime numbah ... :-)

Arfa

Yech. I can't do ragtime very well. Actually, I can't play anything very well (mostly self-taught). Of course, it's not me as I prefer to blame the instrument.

Some ancient and full of mistakes live MP3's of my elevator music, cacophonous noises, and failed experiments. Caveat audiens (Let the listener beware):

Hmmm... 11 years ago and I haven't recorded anything since... Yet another project.

I don't know why you would want to "see" me play. 3-5 minutes of my banging on the synthesizer would certainly be rather boring. Well, maybe a short YouTube video.... Yet another project.