Model railroading with your Droid: Solving electrical issues

Electrodroid is an Android app designed for electronics hobbyists, but it has uses for model railroaders too. Its LED calculator is invaluable when using LEDs to light buildings, cars, locomotive cabs or headlights, or for other projects. Knowing the input voltage, you can then determine what resistors to use to protect the LED.

The voltage drop calculator is useful too, if less obvious. Read more

The trouble with Dell

Note: I wrote this in mid-2010 and, for whatever reason, never posted it. I found it this week. Although the information in it is no longer fresh and new, it’s still useful, so for that reason, I’m posting it now.

Dell is standing on some shaky ground right now. Bill Snyder has a good summary of the problem.

In recent years, Dell computers have, shall I say, made me nervous. Some of it’s been concrete. Some of it’s just been touchy-feely. Now one of those touchy-feely problems is more concrete. Read more

Entry-level troubleshooting

Ars Technica offers a very good, brief guide to troubleshooting computer hardware. Being two pages long, it doesn’t tell you everything, but includes some good tricks, including one I don’t always remember to tell people. To fully discharge a device, unplug it from the wall, remove the battery if it has one, then press and hold down the power button for 10-15 seconds. This discharges any power that could be lingering in the capacitors inside. Read more

Replacing bad capacitors in failed electronics

If you’ve had a piece of electronic gear fail in the last few years, there’s a good chance it’s due to one or more bad capacitors inside. The problem most infamously reared its ugly head on motherboards produced in the middle of the previous decade, but that’s just a place where it’s highly visible. If you had a DTV converter box, a DVD player, or some other device fail in the same timeframe, it may have had the same problem.

If I had a failed motherboard, I’d probably just swap the motherboard. I’m more inclined to fix an LCD monitor or a DTV converter box. Read more

Smart card problems and other Monday weirdness

My boss’ computer had a bad case of the Mondays this week. It took forever to come out of power saving mode, and then when it finally did, it was mostly unresponsive. He couldn’t log in, and the system didn’t even recognize his smartcard reader. The usual fix for a smartcard reader that won’t read and whose light doesn’t blink or come on is to unplug the card reader, wait a few seconds or a minute, and plug it back in, but even that didn’t help this time. Nor did plugging in a known-working reader.

The machine did respond to ctrl-alt-del, and the shutdown options weren’t disabled. Fortunately. So I did a full shutdown, which it did, under protest.
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Thrift-store PCs

In the comments of a recent post I did, reader Glaurung Quena brought up a good topic: secondhand PCs, acquired cheaply, strictly as rebuild fodder.

I like the idea, of course, because I’ve been doing it for years. In the 1990s I built a lot of 486s and Pentiums into former IBM PC/ATs, basically until all the board makers relocated the memory slots into a position that wasn’t clear on the original PC/AT due to a beam that supported its drive bays. And of course the adoption of ATX and MicroATX killed that, at least for a while.

But now ATX has been around as long as the old AT architecture had been when ATX came along, and efforts to replace ATX haven’t been successful. So that trick makes more sense again. Buy a secondhand machine cheaply, intending to re-use the case, and regard anything else inside that happens to be reusable strictly as a bonus. Read more

What to look for in a router

I revisit the topic of what to look for in a router every six or seven years. As important as it always was, I think it’s even more important today, as there are a number of underpowered routers on the market and it’s best to avoid them.

This post originated in 2010. I revised it for 2017 needs, and by the time I was done, I’m not sure much of my 2010 text was left. But that’s OK.

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Beware the leaky capacitors

In case you haven’t heard about it elsewhere, there are some recent motherboards having problems with leaky capacitors.

Basically, the problem is the electrolyte in the capacitors becomes chemically unstable, the capacitor pops and starts leaking, the capacitor stops doing its job, and system stability falls out of the sky.

An EE can do a better job of explaining what a capacitor does, but in my very limited electronics background, every project I ever did used capacitors to eliminate noise or smooth out current.

Abit has come out and acknowledged the problem, but other manufacturers are also said to be affected, including Asus. So this isn’t a problem limited to cut-rate boards, although it wouldn’t surprise me if the cut-rate boards also are affected, because the issue stems from cheap Taiwanese knockoffs of a costlier Japanese design.

Identifying problem boards can be difficult, because the affected caps generally are unlabeled, but not all unlabeled caps are problematic. And, as you can see, my usual advice of sticking with a big-brand motherboard doesn’t save you in this case.

I recall a few years ago an article on one of the newsy tech sites like Cnet or ZDNet said some older models of Soyo motherboards could develop this problem. At the time, Soyo declined to comment. So this isn’t exactly a new problem. If anything, it seems to be cyclical.

If you do have a board that develops the problem, you can probably get it replaced under warranty. If not, a skilled technician can de-solder the bad caps and replace them with higher-quality ones. One technician who performs the service charges $50, which seems very fair to me for de-soldering and re-soldering 28 connections.

It’s definitely not a good first electronics project to try yourself though. If it’s something you want to learn how to do, practice on an old, obsolete motherboard or modem or sound card first. And, naturally, I won’t claim any responsibility.

If you develop the problem, this could also be the excuse you’ve been looking for to upgrade, seeing as it’s getting easy to find new motherboards for $60 or so.

You can read more about it in this IEEE Spectrum article.