As a change of pace from electronics teardowns: I’m taking apart something with no electronics at all: my very old garden hose watering nozzle. It’s been leaking for years, which is why I’ve had to turn the faucet off when this is unused. Otherwise, it wastes water dropping out from the front and the back. But recently it started failing in a new way: there is now a horizontal curtain of water when I pull its lever, spraying water everywhere from just behind the spray pattern adjustment knob. It is finally time for this guy to go, but not before I take a look inside.

A single Philps-head self-tapping plastic screw held the spray pattern selector knob in place.

With the selector knob removed, its seal and detent mechanism falls out easily. The white spring-loaded mechanism pushes into dimples in the selection dial for that satisfying “click” when we are lined up for a spray pattern. The rubber seal has lost its flexibility and became rigid with age. It could no longer seal against water pressure, causing this nozzle’s retirement.

Two more screws were visible and promptly removed, but this plastic piece did not release easily. I broke a bit of the lip (visible in upper-right area of the rim) trying to pull it out. No other fasteners or retention mechanism were visible.

If I could not pull it, perhaps I could push it? I started working on the back end. Unthreading the adjustment nut all the way allowed its removal.

Pushing on the thread, the front face popped free along with the piston assembly. A coat of rust clearly designated regions that had years of water exposure.

Inside the handle body.

Inside the front face.

Intact piston assembly.

I could only partially disassemble the piston assembly. In use the rear seal and its washer moves against the piston shaft and thus could be slid off the end. The spring followed easily.

However, the front seal and the X-shaped plastic guide keeping it centered in the cylinder never had to move and now it is held in place by rust. The plastic guide showing signs of abuse of my removal attempt. Even if replacement seals were available, I would not have been able to replace this particular wear item.

The lever hinge pin is riveted in place, requiring a drill to free it.

And finally, the soft handle surround was cut free of the metal core with a box-cutter knife. Doing this reminded me of that scene in Terminator 2 where the T-800 cut off living tissue covering its arm to expose the metal endoskeleton.

This Taylor food thermometer display went blank and stayed blank even when given fresh batteries, so it’s getting the teardown treatment before disposal. It appears to be a design that the company has made for many years with slight variations, here is a close cousin I found on Amazon. (*) I’ve found no mentions of repair instructions or replacement parts, this is a disposable device.

The first thing I wanted to check is construction of the temperature probe. There were two possibilities:

1. The temperature probe is mostly metal, and the sensor is near where the wire is attached. This would be dependent on a metal with high heat conductivity to carry heat from the tip of the probe to the sensor at its base.
2. The temperature probe is mostly hollow tube, and wires run the entire length of the probe to a sensor at the tip.

I started opening it up and got this far before slicing myself open on a sharp metal edge.

With a ritual blood sacrifice to the teardown gods, I decided to stop here. It is far enough for me to conclude that possibility #2 is correct and the probe is mostly hollow tube with the sensor at the tip.

Next I started prying against the shiny top surface of the device and found it was merely a cosmetic facade held on with glue and not hiding any fasteners underneath.

Four fasteners were visible behind the display so I started work there.

There is a piezo sound element embedded in the back, and a circuit board inside. Under that black blob is likely a chip that runs the whole show. What struck me are the areas to the left of the blob: there are a few round test points, but many more rectangular pads for components that aren’t there. Are they for calibration? Are they for adjustment? Are they to activate/deactivate features for other products in the lineup? Maybe a combination of all of them?

I see a single screw for the base. Removing that screw freed a small piece of plastic but did not free the entire base. However, it did let me see inside the base and distinct signs of additional fasteners.

Aha, I forgot to check for fasteners hidden under squishy feet.

With those screws removed, we can see the base has no active components. It has the battery enclosure, socket for the temperature probe, and a circuit board for all the switches and buttons to operate the device. All the components appear to be in good shape, I see no obvious signs of damage that might explain why the device stopped working.

The display is a custom LCD unit held on with the squishy conductive stuff I’ve seen before in tearing down electronics but didn’t know anything about. This time I went online and found this electronics StackExchange thread. Which linked to this one. Formally “Elastomeric connector” and less formally “zebra strips” (though a search with those terms also need to have “electronic” in the keyword list or else we’d get stuff about zebra the animal.)

I don’t plan on keeping the circuit board or any of the components on board, but I’ll hang on to the LCD for the moment. If I get around to probing the LCD in the future I’ll need to fabricate my own circuit board to make contact with the zebra strip. I can take this picture showing the connector pitch, but sadly I’ve already lost horizontal alignment reference and that’ll be a problem I have to tackle later.

(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

While organizing my workshop, I labeled a lot of things with my label maker (Brother P-Touch PT-D400) and used up a cartridge. A common complaint with these TZe label tape cartridges is that they are really expensive. So now that I have an empty cartridge, I thought I would take it apart to see if I can see anything that justifies its expense. It turned out to be far more sophisticated than I had originally expected, but I still don’t know if I would call its cost “reasonable”. Plus I found an interesting security concern. Don’t use label makers for confidential information!

The only thing we can really see from the outside is a horizontal window designed to let us see how much tape is left. When full, there’s white visible behind the light blue area. That white spool’s diameter decreases as the tape is consumed, gradually running to what we see in this picture where very little white is visible behind the blue.

Looking around the perimeter, I see several little clips holding the lid to the body plus this white tag telling me what label tape is inside. I expect that I would have to cut this white tag along the seam, pop those little clips loose, and it should fall apart.

It did not.

Majority of holding force actually came from these posts that fit very tightly into their sockets, not the clips or the sticker. Dimension precision in injection-molded plastic is directly correlated to cost, so that’s where some of the money went: it’s pretty expensive to keep these posts and their corresponding sockets within the exact dimensions to fit and grip tightly.

After I opened up the cartridge, I see I had drastically underestimated the complexity inside. There are actually four spools, a few rollers, and many guides to keep three tapes of materials flowing properly.

Here are all the components of the cartridge. Multiple spools, and a few springs to maintain tension. I had expected a single spool of tape that gets spit out, so this is far more complex than I had anticipated. There are actually three spools of material: The white adhesive backing, the black ink (with take-up reel), and the clear laminate layer.

Here is a closeup of the clear laminate spool and the white adhesive backing spool. The clear laminate spool has black stripes in this picture because that’s how the cartridge signals the end. There were ~20cm left of this zebra stripe, not that I can think of much I could do with it.

Here is the other side, showing the adhesive backing still usable on what’s left of the white reel. It looks like remaining white backing can still function as double-sided tape if I wanted to put it to work.

The black ink tape was a surprise. It is a pair: a dispenser reel for fresh material and a takeup reel for used ink. What’s super interesting here is that the takeup reel has a clearly legible negative image of everything that has been printed. Unspooling the takeup reel a bit, we can clearly see that my most recent label was for a batch DC buck converters showing their adjustable voltage range and maximum of 5 amps capacity.

A valuable lesson from this teardown: avoid confidential information when using a label maker, because a motivated dumpster-diver can read that information off your discarded empty label tape cartridges.