Archive for the ‘Misc Stuff’ Category

IMac Repair Update

Thursday, December 14th, 2017

My previous post on a couple of attempts at an IMac repair was here:

I glad to report that I’m convinced that the problem is resolved, as the unexpected power off issue has completely vanished.

IMac repair

Wednesday, October 11th, 2017

I have a 5 year old IMac that recently started to act up in a most annoying fashion. Every couple of hours it would shut itself off, with absolutely no warning.

Right from the first occurrence, this felt like a power supply issue. I could power it back up, simply by unplugging the unit, waiting a few minutes, and turning it back on.

Research on the internet, revealed that others had similar issues, and also how to get inside the unit. One symptom of this failure is that the sys log showed the last restart was done to loss of power, not some kind of crash.

Knowing how expensive Apple service would likely be, I decided to look into fixing it myself. I carefully worked a putty knife between the display and the chassis to get it open. What a horrible design, it’s so bad that it’s hard to comprehend that Apple would ship something like that. I managed to crack one corner of the glass getting it open, but it wasn’t a fatal crack, and the display remains perfectly usable.

Anyway, I removed and examined the power supply, looking for the telltale signs of a damaged component, but couldn’t find anything obviously wrong. I decided to reassemble the unit, hoping that perhaps one of the connectors was intermittent. I decided to use duct tape to reattach the screen, in case I might need to attempt something different, like replacing the power supply, altogether, in order to get the system fixed.

IMac held together with duct tape

IMac held together with duct tape

After powering up and running for a few days, the problem returned, so I knew it wasn’t a faulty connector. I decided to take one more look at the power supply before ordering a replacement. This time, I repeated the scan for obviously fried components, but found none. I did notice that the soldering on a few of the through hole components, just didn’t look that good. The solder job looked like the heat wasn’t enough to draw the solder down into the holes, so the solder was kind of balled up on the legs of these parts. Getting the heat right on a board like this, probably isn’t easy, as it contains a mix of small surface mount parts and through hole parts, that are connected to relatively large heat sinks.

I decided to reflow the solder on the suspect components and see if the system would work more reliably. I went ahead and took a shot at it and put the system back together (with duct tape). I’m still not sure if I fixed it, but three weeks later, I haven’t seen a reoccurrence of the random power off. However, it wouldn’t surprise me at all if putting up this post doesn’t cause an immediate reoccurance of the issue!

Repairing an Old Automobile Tape Deck

Sunday, September 24th, 2017

Quite of a bit of the stuff I own and use everyday is, let’s just say old. This includes a 1988 Mustang convertible that sometimes becomes my daily driver. This car is what they call “bone stock”, and I like to keep it that way, though there can be challenges with it. One of the challenges is the sound system that gives you the option of a FM/AM radio or cassette tapes. Lately I’ve been relying mostly on the cassette tape player.

The problem with the cassette tape player is that after so many years, the pinch roller losses it’s grip, and the tape plays at too high a speed, giving you awful Donald Duck sounds. The last time that happened, I found an exact replacement tape deck on eBay and simply swapped it in. Well, eventually the replacement deck started exhibiting the same issue. This time around, though those decks can still be found on eBay, I figured that I would try to fix it. This became a multi-week adventure, as I stripped down both decks, swapping the best components of the replacement deck onto the original deck, which I had kept stashed in the attic. In the end, I ended up with a pile of parts and a working deck, but it wasn’t easy.

Radio in Pieces

Radio in Pieces

Here is some of the stuff that I did to get a working tape deck.

  • The original deck had chipped corners on the front bezel, so I swapped in the bezel from the replacement deck. In doing this swap, some of the wires on the flat flex cable connecting the front PCB to the main PCB were damaged, so jumper wires had to be added to repair this.
  • The backlight for the original deck’s display was gone, so I had to swap in the backlight from the replacement deck. This might actually be the light that was originally in that deck.
  • A power supply trace on the main PCB was found to be broken and had to be jumpered over.
  • I’m not sure, but I think the original tape deck had an issue with a switch, resulting in the tape playing at fast forward speed, similar to the slipping pinch roller sound. Rather than troubleshoot, I ended up swapping in the replacement deck, after cleaning the pinch rollers, which is was next step.
  • The pinch rollers on the replacement deck were cleaned, as best I could. In fact, if I had done this in the first place, that is all that I would have had to do.
  • ENIAC in Action Book Review

    Thursday, June 22nd, 2017

    First of all, let me tell you that I’ve had a hard time writing this review, as I enjoyed reading the book quite a bit, but I think that the book is not for everyone. I really wanted to write that everyone should read this book, as the reader will learn a lot about what happens in new product development, which is more relevant these days, than ever.

    Anyway here goes the rest of my attempt of a review.

    Eniac in Action by Thomas Haigh, Mark Priestley and Crispin Rope is a different kind of book in some ways. First off, it goes into a significant amount of technical detail. Much of this detail would be hard for a “lay” reader to understand. This is the part that I think may cause problems with some readers. Technical detail aside, where the book really shines is how it describes in detail, the process that it took to create, maintain and eventually enhance ENIAC, a fairly complex implementation of a new technology.

    The development of ENIAC was filled with many challenges and obstacles, which the authors describe in a very engaging style. The details of ENIAC development are unique. However, in my opinion, when compared to the process of developmenting other complex systems, there isn’t much that is really different about the ENIAC. That is why I think everyone should read this book. You will get an understanding of just how hard it is to “change the world” with revolutionary new products and systems. Development of complex, new systems are always problematic and take time to sort out. Certain people in the process will get most of the credit and many, many people will be forgotten.

    Reading ENIAC in Action will give you a glimpse of one such project. When reading it, keep in mind that there are many engineering teams around the world currently engaged in similiarly daunting tasks.

    Some Thoughts about Happiness

    Tuesday, October 25th, 2016

    When Thomas Jefferson wrote the first draft of the Declaration of Independence, he wrote of three inalienable rights. Among the three, was the “pursuit of happiness”. While some people think that the phrase, “pursuit of happiness” is about the acquiring of material wealth, as portrayed in the recent movie by the same name. In reality, that isn’t the case. Scholars know that Jefferson admired Epicurus, a Greek philosopher, who founded a system of philosophy. The following description of Epicurianism is from Wikipedia:

    The philosophy originated by Epicurus propounded an ethic of individual pleasure as the sole or chief good in life. Hence, Epicurus advocated living in such a way as to derive the greatest amount of pleasure possible during one’s lifetime, yet doing so moderately in order to avoid the suffering incurred by overindulgence in such pleasure. The emphasis was placed on pleasures of the mind rather than on physical pleasures. Therefore, according to Epicurus, with whom a person eats is of greater importance than what is eaten.

    So Jefferson was advocating a pursuit of happiness as an unalienable right, he was in essence advocating a pursuit of Epicureanism philosophy as a fundamental aspect of a free man’s life.

    You might wonder why I am talking about Epicureanism. Why is it so important, that I would make an effort to share these ideas with you.

    Well, I think that happiness is something that you should pursue, and it is absolutely worth pursuing. Happiness does not necessarily come automatically with other goals like attaining an education, advancement at work, raising a family, or striving for any other goal. Happiness should be a goal unto itself and you should pursue it, the same way that you might pursue your other goals. Those other goals may or may not bring you happiness, and, at best, attaining those other goals most likely will only bring you temporary happiness. Therefore, you should make happiness a goal unto itself.

    Make sure that whatever you do in life, make sure that you set aside a little time each week to think about what gives you happiness and make finding a little happiness each week, one of your goals for that week. You may not succeed every week, but just thinking about it and working on a plan, should provide some hope for the next week. Furthermore, I believe you should encourage and help your partners, family and friends to find a little happiness each week.

    This essay was written over the spring and summer of 2016 by Mike Willegal

    Where Did All The Moths Come From?

    Wednesday, June 1st, 2016

    Over the last few years, we have had a plague of small moths, especially in the spring time. There are so many, that the larva from these moths defoliate certain types of trees in the spring. So far, these trees have managed to survive, but I’m wondering how many more years that they will be able to tolerate this. The moths are attacted to the lights inside the house at night. There are so many moths, that they get into the house almost every time you open a door at night.

    While discussing the disapperance of the Bats with a neighbor the other day, I think I came up with the likely reason that the moth population has run amok. Bats eat moths and other similar sized flying insects, such as dragonflys. With the bats out of the picture, the moths have had little to curb their population, except the available food supply.

    Note that bats typically do not eat mosquitos, since mosquitos are too small too provide much nourishment. Dragonflys do eat mosquitos, so with the bats gone, there may also be a reduction in the mosquito population as one consumer of the dragonfly population has been taken out of the picture. Come to think of it, the mosquito population does seems to be low for this time of year.

    The balance of nature sure is sensitive and it’s surprising to see it out of whack in our own backyard.

    PCB and kit stocking status

    Saturday, February 27th, 2016

    I now have everything that I normally stock on hand – except SCELBI front panels.

    I was a bit behind on things, but today I shipped a few items that I owed people, so am caught up, with the exception of those SCELBI front panels.

    In addition, due to popular demand, I made a new run of Brain Board kits. I tested an example earlier in the week, and except for a bad 74LS74 IC, I found they work fine. I’ll have to go through my stock of 74LS74’s and test them before finishing putting together kits. With luck, I’ll have kits ready to ship by next weekend. Watch for an update in the next few days before sending money.

    Where Did My Neighborhood Bats Go?

    Thursday, December 10th, 2015

    One evening last summer, during an evening party, I got out my bat detector. Much to my surprise, I was unable to detect any bats. This struck me as very odd, since during previous summers, I never had any difficulty detecting plenty of bats. Well, I just found out what happened to my neighborhood bats. There is a disease, known as White Nose Syndrome, attacking colonies of bats throughout the world. In many cases, bat populations have plumeted, with some species facing possible extinction.

    The real question I have, is, with such a disasterous decline in bat populations, why didn’t news of this reach me through regular news channels. I only discovered the problem, when I stumbled upon the story when I looked on the web for a link to the instructions I used to build my bat detector.

    I’ve been thinking for some time that major English language news agencys have a narrow focus on a few topics, instead of covering a broad range of news. That millions of bats could die, some literally in my back yard, and that the news agencys leave me unaware seems almost criminal. Instead, we get bombarded with the news about a few wacko’s killing inocent people who happen to be in the wrong place at the wrong time.

    Maybe, due to high costs and tremendous competition, the major news agencies are limiting news to what they can sell, not what an editor thinks we need to know. It seems, at least at major news agencies, the role of that editor, the person that promoted a point of view, has been replaced by a marketing person. To me, it’s a shame.

    Apple Service Sucks

    Wednesday, July 15th, 2015

    I have had two negative experiences.

    A while back, a Powerbook trackpad failed while still under service contract and Apple didn’t want to fix it because the service person claimed something was spilled on it. Though the machine was used by other family members, I know of no actual spill. They wanted something like $900 to repair it. I ended up getting an aftermarket trackpad off of ebay and fixing it myself for $40. So much for the extended warentee. I must admit that a service manager called me after I sent negative response to their after service questionnaire. He offered to have another look at it, but by then, I decided I could handle it, myself.

    My iMac hard drive was recently recalled due to a high failure rate. I made an appointment and took it in to their store. Result – after waiting around for a while, someone checked out my machine and made sure that it operatated correctly, found that they had the replacement drive in stock, then said that they would have it ready in 3 to 5 days. I asked if they were going to migrate the data. The answer was no, it was going to take so long because changing hard-drives was a “delicate” operation. 5 days to change a hard drive, without migrating data – Apple, give me a break – you can do better than that.

    While waiting for help on the iMac hard drive, a woman came in complaining about intermittent WI-FI connectivity with her iPhone. I can’t imagine the Apple “genius” solving that problem.

    Old School Engineering

    Wednesday, June 10th, 2015

    I just viewed Dave Jone’s latest video blog about the Sony Walkman. For some reason, I decided to download the service manual and have a look. One thing that I immediately noticed, was the lettering on the schematic appears to be another example of Leroy Lettering.

    This caused me to reflect a little bit about my first year or two of college and my first job in industry. Before discovering computer science, I started out in a mechanical engineering program. The first engineering oriented courses you took, were drafting courses. I had no trouble with perspective and different technical aspects of drawing. However, I really had trouble creating drawings that looked nice, clean and sharp. There was no mention of Leroy or any other mechanical lettering system, so we had to hand letter our work. To this day, I don’t have the hand of an artist, and I think that lack of natural artistic ability held me back in that program. The skill of an artist, developed or natural is something that is apparent in a well done engineering drawing or schematic.

    In years gone by, many engineers would spend their workday at a drafting board. I started my first co-op engineering job, in the late 70’s. That first company that I worked for, still had a drafting department for creating PCB layouts, as well as an art department that did the artwork for manuals as well as marketing material. The “uniform” of many of the experienced engineers was a white shirt, dark pants, a dark tie and a pocket protector. Second level managers omitted the pocket protector and added a sport coat. It’s basically the look of the NASA mission control team for the Apollo program.

    A few years later, in the early 80s, I remember going for a job interview at IBM’s small system division. That was the first home of the IBM PC which was located in Boca Raton, Florida. Almost all the engineers there still wore that “uniform”. I did see one guy wearing a colorful shirt and jeans. He stuck out like a sore thumb. The IBM employee that was with me at that moment, pointed him out, and said he didn’t really fit in to the culture.

    How times have changed.