Amazing 30 Year Old Aquarium Filter Repairs

One of the most amazing electrical-mechanical devices that I have ever owned is my Eheim 2213 canister filter. This is a water filter that I have used to help maintain water quality in my 55 gallon freshwater aquarium. This filter has been running continuously since I installed this aquarium probably around 1994 or 1995, close to 30 years ago. Every few months I cleaned out the media, but otherwise, it just runs and runs. About 10 years ago, I replaced the hoses that had gotten hard, but other than periodic cleaning, it has received no additional maintenance. A few years ago the pump started getting a bit noisy, but it kept running until a few days ago when it stopped. Inspection revealed that the impeller shaft and impeller were just plain worn out. A quick search on the internet revealed that replacement parts were still available with next-day delivery, so I ordered new parts.

The parts arrived the next day and I replaced the impeller and shaft. Turning it back on, it picked up again just where it left off. I am enormously impressed with this filter and the ability to get repair parts with one-day delivery.

I also have used an Optima A-807 air pump for a similar amount of time that has had its diaphragm replaced once. That has also been a pretty impressive run.

The only thing I can think of that that comes close in reliability is an Amana refrigerator that I replaced after 22 years of service. That refrigerator was replaced because of a remodeling of my kitchen that made that refrigerator unsuitable for the new layout, not because it failed.

I have a few other devices that are older and still work, but none of those are continuously operated and all of them have had multiple faults over the years.

Gettysburg – Cemetery Ridge Photos – 1964 and 2021

In 1964, my family went on a 2 week camping trip. We journeyed from Wisconsin to Washington D.C. and back. We visited many sites over the course of those two weeks. The first place we stopped at was Gettysburg National Military Park where I fell off a cannon and developed a life-long interest in the American Civil War. Here is a picture of me on a cannon, just moments before I fell off of it.

Thomas's battery-then
Thomas’s battery-then

This was taken on Kodachrome slide film with a pretty basic 35mm rangefinder camera. This was a popular way to record vacations back in those days. A few years ago I scanned all the surviving slides from that trip. At the time I scanned those slides, I did some investigation and figured out that the monument next to that cannon, is the monument to Thomas’s Battery, Battery C, of the 4th US Artillery, which was part of the Army of Potomac Artillery Reserve. The key to figuring out where the picture was taken was that there was another picture in this sequence taken of the Pennsylvania Memorial. The Pennsylvania Memorial is just across the road to the right of where this picture was taken.

This summer, as part of a long road trip, I stopped by Gettysburg for a few hours. I decided that I had to stop by the Thomas’s Battery Monument and take another picture. This is how this location looked like in the summer of 2021.

Thomas's battery now
Thomas’s battery now

The area in front of the monument isn’t mowed, so I really couldn’t get a picture from the exact same angle, but this gives you an idea how the site looks like these days.

Book Review – A Campaign of Giants – The Battle For Petersburg: Volume 1: From the Crossing of the James to the Crater – A. Wilson Greene

I’ve long held an interest in the siege of Petersburg, which was the decisive campaign that lead to the end of the American Civil War. Despite the importance of this siege, books that cover it in detail are few in number, especially when compared with detailed coverage of most of the great battles of 1862 and 1863. When I heard of this new book in 2018, which promised the coverage that I was looking for, I knew I had to read it and I bought a copy soon after it was released.

A Campaign of Giants
A Campaign of Giants

Though the book has good reviews, currently rating 4.6 on Amazon, it took me two years to finish it. Though very well written, I found parts of the book hard to read. I think that is because my point of view differs greatly from that of the author. The author is extremely critical of the generalship of the Northern leaders. While Greene mentions some of the mistakes of the Southern commanders, it’s almost as if Greene was still propagating some aspects of the myth of the “Lost Cause.” In my mind, Greene doesn’t really appear to understand the difficulty of what Grant and his armies were attempting to achieve.

Though this is a battle book, I found coverage of the various engagements, inconsistent. With the vast majority of these kinds of books, the author, after describing a battle, will summarize the results in terms of ground lost or gained and resulting casualties. This book is no different and some of the smaller engagements are described in this fashion, with little to no detail as to what happened. To me, this approach strikes me as completely ignoring the horrors of war, almost antiseptic in nature. The following example shows how a clash that cost 140 Confederate casualties and an unreported number of Federal casualties, is covered in only two sentences. I understand how a book covering so many events can only devote so much text to such a small engagement, but it still bothered me a bit.

However, at the other end of the spectrum, the description of the Battle of the Crater is extremely graphic and detailed. Every American should read Greene’s account of that battle. This account should dispel any misconceptions modern Americans have about the Civil War being a “clean” war. In actuality, it was an ugly, dirty, horrid affair. This account also explores the horrors of racism that persists in our society to this very day.

Just to end this review on a positive note, I found the description of Wilson’s raid very engaging and interesting, maybe because I knew very little about the raid before reading this book.

Finally, since I’m done with this book, and I don’t have room on my shelves for more books, I’ll send my copy to the first of my blog readers that reaches out to me expressing an interest in reading it.

Debugging the SCELBI Power Supply

I had a bit of trouble debugging the 5 volt side of this power supply. First symptoms I noticed was an inability to regulate under load. As the load increased the output voltage dropped significantly to the point where the computer would not work. In my mind, this probably meant that the regulator portion wasn’t working.

These sort of Power-One linear supplies use a uA723 regulator to do the job. You feed reference voltage and output voltage (usually divided by a resistor network) into the regulator and the output of this chip controls one or more power transistors to supply the desired voltage. You can find more about these supplies on this nice Power-One hacker page.

Though the Power-One linear supplies are all similar in design, they differ in details. I made a schematic of this particular power supply so that I could properly debug it.

Power-One Schematic
Power-One Schematic

After much probing, I could find no issues with the regulator circuit or the regulator chip. This really confused me, as the power supply regulation wasn’t operating correctly. After some hard thinking, I wondered if the problem might actually be with my measurement. Since my oscilloscope was broken, I switched my DMM to AC mode and as soon as a load was applied, I detected a several volts of ripple. Using a DMM to check ripple by putting it into AC mode is a trick that I learned somewhere along the line and has come in handy a number of times.

Realizing that most likely the smoothing capacitor, wasn’t smoothing, I jumpered in a fairly large capacity smoothing capacitor that I had in my stash. Sure enough, the ripple disappeared and the power supply output remained stable under different loads, just like it was supposed to.

I ordered an appropriate replacement and a spare. I replaced the smoothing capacitor and the power supply worked flawlessly for the remainder of this original SCELBI-8B’s checkout.

This isn’t the quite the end of the story. After I returned the system to the owner, the power supply failed again. Since symptoms were the same as before, I thought that perhaps the replacement capacitor failed during shipping, I sent a second capacitor to the owner, who wired it in parallel to the replacement cap, which solved the issue (again). Whenever I order parts, I almost always order spares, as shipping is often more expensive than the parts themselves. Having a spare on hand certainly was helpful this time around.

I’m not sure what happened during shipping of this system. Generally, I’m pretty reluctant to repair old computers, because of the high risk of new issues appearing during return shipping. I only took on this job because of the rarity of a SCELBI-8B and the chance I would have to further document an example.

SCELBI Style Enclosure for Scopewriter

I built a SCELBI Style enclosure for my Scopewriter interface.

SCELBI Scopewriter Interface Exterior
SCELBI Scopewriter Interface Exterior

Instead of using rub on lettering, I printed decals on decal paper using a laser printer. The results are similar to rub on transfer lettering, but not quite as nice, as, if you look really close, you can see the transparent edge of the decal. The big advantage of decals is that I can print them at home for the cost of the decal paper.

The interior looks pretty much like original SCELBI peripherals. One mistake I made, was to build it upside down, when compared to original SCELBI peripherals. Not a wonderful thing, but at least it will easier to display at shows that I sometimes attend.

Interior SCELBI Scopewriter Interface Enclosure
Interior SCELBI Scopewriter Interface Enclosure

iMac repair update

Back in this post from almost a year ago, I noted how I “repaired” an iMac power supply by reflowing some suspect solder joints. Well the repair lasted less than a year, when the problem returned. After attempting another go at reflowing solder joints, which had no effect, I ended up getting and installing a new supply. Hopefully the new supply lasts more than a year.

Views From A Couple of Mountain Tops

While I enjoy my indoor hobbies, I also will rarely pass up the opportunity to enjoy the outdoors. Here are pictures from the top of a couple of mountains that I have climbed in the last year.

On Top of Mount Bierstadt

On Top of Mount Bierstadt

I climbed Mount Bierstadt in Colorado last August. This was my first fourteener, so called because it is over 14,000 feet high. It was a beautiful day and I enjoyed the climb, and yes, I did notice the effect of the thinner air at high altitude. This is one of easiest fourteerers in Colorado. I can only imagine that one of the more difficult ones would be pretty challenging, and most likely dangerous.

Welch-Dickey Trail

Welch-Dickey Trail

This is a picture of Mount Dickey from the top of Mount Welch, which I took last weekend. This is also a first. The first time I hiked a mountain covered with snow and ice. It wasn’t as hard as I expected, but I was expecting a major challenge. I was lucky my friends were able to loan me micro-spikes which turned an impossible situation into just a somewhat challenging situation.

IMac repair

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!