Category: Stuff

Retiring an old hard drive

I didn’t remember when I bought this hard drive (I thought 2004). It was an HP product with an unalterable HP partition, designed for Windows backups. Which I probably never used it for. That was a bother, but even more of a bother was my trying to overwrite the disk so I could give it away. My command-line Linux magic simply rendered it unusable, unmountable, impossible to format in Linux or MacOS.

So, impossible to erase. All my data still on there.

However, that raises a question:

Short answer: That being said, if you just want a quick rule of thumb for how long you can expect the hard drive in your laptop should last, we’d say you should be prepared for disk failure after three years of use. source

Of course, this was not in constant use. But, at 13 years and four months, it is now retired. And my data safe.

The scanner

I almost never discard anything complex without trying to take it apart and learn something from it. Non-destructively, if possible.

When my 13-year-old scanner abruptly stopped working, I quickly discovered it would not be coming apart without a fight. There’s essentially nothing you couldn’t see just by looking through the glass, so no real surprises, other than the motor being remarkably small – barely wider than a pencil.

The main thing I learned, though, was that this was designed to NEVER be taken apart – the way the glass was sealed … and then it struck me: of course not. It was assembled in a dust-free environment and it was essential that no dust ever had a chance to get inside!

Armature balancing and worm gear

I got back to the circular saw tear down which left off with a worm gear assembly that I couldn’t get apart. A couple weeks later I remember it, try again and it slides out like it’s greased. Because it is.

It turns out the worm gear reduces the rotation speed by a factor of six, meaning the motor itself was spinning at 27,000 RPM. Yikes!

That solved, another question remains: what are all the little indents in the armature for?

UPDATE: I posted this question on ElectricalEngineering on Reddit, speculating they had to do with balancing. Yes, I learned, they are balancing cuts. The post has been viewed over 1,300 time in 24 hours.

Circular saw dissection

Cutting up 2×6″ jungle hardwood proved too much for the used German circular saw I bought twelve years ago for USD 40 (I’ve gotten my money’s worth ;-). I thought it needed new brushes, but no, I fried the armature. Quite interesting taking it apart; some simple and some very tricky. I’m still working on the worm gear assembly. Why does it have one?

The repair shop sold me a Skil that they refurbished. 1400 watts versus 1200 on this one; 5,700 RPM versus 4,500. The thing is a BEAST!

UPS dissection

From one day to the next, a UPS unit died. I charged it up, checked battery output – only 8 volts where there should be 12. Meanwhile, no electricity passing through, meaning it doesn’t even have any use as a surge protector. So, tear it apart. Nothing too challenging,

the exception being the outlets, which appear to have been snapped in place and soldered. No big deal; happy to leave it at that. Nowhere near as much fun as tearing apart other things, like a laser printer.

Angle grinder

Post mortem for la máquina

I rarely throw away anything that can be taken apart, without taking it apart. La máquina actually had a few challenging bits, and I had to cut apart a bit of a plastic fan to remove screws, so it remains a mystery to me as to how that part of the thing was assembled.

The gear assembly with bevel gears that change the rotation 90 degrees. Quite remarkable to imagine designing or manufacturing things like this.

And this clever spline. The rounded bit goes into the rounded indentation on the shaft, protruding a bit, and the gear slides over it, so that it has to spin when the shaft spins.

Once assembled, it’s held in place by the gear it mates to. OK, enough of this. I must have something more important to do….

Angle grinder, burned out

Cutting a plastic barrel in half to make planters, I noticed the angle grinder (almoradora here, called la máquina by Mexicans) was slowing down. I also noticed pain in a fingertip that I couldn’t quite place.

Turns out it was heat, and moments later I saw a bright flash and smoke.

After 12 years, la maquina is dead. Long live la maquina!

A first – changing a light bulb

I have lived in ten houses in the last 35 years, four rented and six owned. Today was the first time in 67 years on this planet that I have had to change a refrigerator light bulb. I had never even considered the idea before. I thought, Isn’t that strange? until I realized that, at 11-½ years, this is the longest I’ve lived in one house continuously since age 15. And in the last 35 years, of course, with an average of 3.5 years, by far.

We had less memory then

Though we’ve had Mac Minis for almost ten years, I only today discovered they have a slot for an SDXC memory card. I have some of those somewhere, I thought.

Yikes! 16 megabytes? That must be from our first digital camera 20 years ago. Each would hold exactly three photos now at 10 megapixels.

I was reminded of the 128 megabyte flash drive I ran across recently.

Not really sure why I hang on to these things.