The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: Repairs

If it used to work, it can work again

  • Cheap WS2812 RGB LEDs: Continuing Failures

    Three more knockoff Neopixels failed in the last few weeks, including one that can’t possibly suffer any thermal stress:

    Halogen bulb brass cap - overview
    Halogen bulb brass cap – overview

    I wrapped the halogen bulb in a shop towel, laid the ersatz heatsink against an anvil (actually, it was a microwave transformer on the Squidwrench operating table), whacked a chisel into the epoxy joint, and met with complete success:

    Failed WS2812 LED - ersatz heatsink
    Failed WS2812 LED – ersatz heatsink

    Having epoxied the PCB and braid in place, there was nothing for it but to drill the guts out of the brass cap:

    Failed WS2812 LED - drilling
    Failed WS2812 LED – drilling

    Which produced a pile of debris in addition to the swarf:

    Failed WS2812 LED - debris
    Failed WS2812 LED – debris

    The brass cap emerged unscathed, which was just about as good as I could possibly hope for.

    The base LED in this 21HB5A also failed:

    21HB5A on platter - orange green
    21HB5A on platter – orange green

    Soooo I had to unsolder the plate lead and Arduino connections to extract the bottom PCB; fortunately, that was just a press-fit into the base.

    I should mount a 3.5 mm stereo jack on the platter and run the plate lead into a nice, albeit cheap, knurled metal plug, so I can dismount both the tube and the plate lead without any hassle. Right now, the tube can come out of the socket, but the plate lead passes through the platter.

    For whatever it’s worth, all of the dead WS2812 LEDs pass the Josh Sharpie Test, so these failures don’t (seem to) involve poor encapsulation.

  • X10 Transceiver Case Plastic: End Of Life, Redux

    Another X10 RF transciever, this one made for IBM (!) a long time ago, emerged from the heap with its case falling apart: the plastic bosses that should anchor the screws had broken off, then cracked radially. Given that I was probably going to toss it anyway, for reasons that will soon be obvious, I tried repairing the bosses just for practice.

    Stuffing the boss fragments into close-fitting brass tubes, with a dash of IPS #3 on the broken faces, put them back together reasonably well:

    HD501 X10 Transceiver - plastic boss gluing
    HD501 X10 Transceiver – plastic boss gluing

    More IPS #3 and a pair of clamps stuck the bosses back on the case:

    HD501 X10 Transceiver - plastic boss assembly
    HD501 X10 Transceiver – plastic boss assembly

    Note the dark smudge on the inside of the case. Even though nothing on the PCB looked particularly overheated, Soot Is Sign of Bad Electrical Health.

    And it turned out neither the bonds nor the plastic were up to the task. A day after successfully reassembling the transceiver, the bosses failed along new cracks and crumbled into different fragments.

    I applied a Kapton tape belly band around the case halves, verified that the transceiver no longer produced reliable X10 commands, and executed ++recycle_pile.

    So it goes.

  • Kenmore Progressive Vacuum Cleaner Carpet Brush Disassembly

    The beater bar found and ingested a remarkably long strip of carpet yarn, resulting in a sudden stop and an acute need for disassembly. In the unlikely event that happens again:

    • Remove hose
    • Release latch to lay hose fitting flat
    • Remove two obvious screws
    • Pry rear latches adjacent to hose fitting to release rear of top cover
    • Pry side latches to release middle of top cover
    • Pull rear of top cover away from base
    • Disengage latches along front of beater bar

    Those places, neatly marked for future reference, with the top cover against the floor:

    Kenmore Progressive vacuum - carpet brush - disassembly latches
    Kenmore Progressive vacuum – carpet brush – disassembly latches

    With the cover off, the beater bar lifts out and you can easily unwind the mess.

  • Forester: TPMS FTW, Redux

    Now I know the Forester’s TPMS icon blinks on 1000 feet from a cold start with 12 psi in the offending tire. I returned home and pulled this from a sipe in the left rear tire:

    Road debris - blade fragment
    Road debris – blade fragment

    It’s atop a 0.1 inch grid.

    The flat side on the right rode tangent to the tire surface, recessed slightly below the tread, and pretty much invisible inside the sipe. Of course, the point punched through the tire’s steel belt and let the wind out, ever so slowly.

    I initially thought it was a utility knife blade fragment, but under the microscope it looks more like a saw blade tooth. It’s obviously been kicking around on the road for quite a while; back in the day, they occasionally swept the roads, but that was then and this is now.

    Makes me glad I didn’t buy four new tires after the last flat. I suppose installing two plugs in the same tire counts as a net loss, but they’re small, widely separated injuries and that’s how it’ll roll.

    For the record: with 14 k miles on the tires, tread wear = 2/32 inch of the original 6/32 inch depth.

    Those tires should last another 30 k miles at our current pace, although I expect more random debris will kill one stone cold dead before that.

  • X10 TM751 RF Transciever: End of Life

    X10 control from the two HR12A remotes got much worse over the last few months and eventually failed completely, which meant I had to actually walk over to the lights and click the switches. Not to be tolerated, sez I, so I would walk to the bedroom and poke the appropriate buttons on the wired controller (long since obsolete) by the bed. That worked perfectly, which eventually convinced me to dismantle the TM 751 transceiver.

    It’s not good when soot plates the case:

    X10 TM751 - Smoked case
    X10 TM751 – Smoked case

    I like how they capacitively coupled RF from the antenna for complete line-voltage isolation.

    The PCB looked like it got rather hot over there on the left side:

    X10 TM751 - Overheated PCB
    X10 TM751 – Overheated PCB

    A Zener diode on the component side of the PCB looked a bit toasty, so I decided this gadget had passed its best-used-by-date and dropped it in the electronics recycling box (after harvesting the antenna, just in case).

    A new-in-box TM 751 from eBay arrived a few days ago and works just fine.

    Done!

     

  • Truth In Labeling: Bike Tube Division

    The lumpy surface of the Michelin Pro-Tek Max tubes now in the back tire of our bikes can’t be patched, which means (being that type of guy) I must carry along a spare tube in addition to a handful of CO2 cartridges. So, having cleaned out my tube stash, I ordered a pair from an Amazon supplier, not my usual bottom-dollar eBay suppliers, clearly described as fitting the Schwalbe Marathon Plus 700x35C tires.

    The Amazon listing and the box label agreed, but (being that type of guy) I just had to extract the tube to see what I got:

    Meetlocks tube size mismatch
    Meetlocks tube size mismatch

    Huh.

    According to the seller, who speaks and writes English far better than I can handle Mandarin (or whatever):

    Yes, you are right, you also didn’t bought wrong items for your tire. we marked the 700×28-32, just for our manufacture to difference from another big size from 700/35-45C, because if we marked the size 700×28-35C, sometimes , the worker will packing 700×35-45c into the packing, and let the tube can not used for the 700x35c customer..

    Huh.

    It turns out the tube has 35-38 embossed into the rubber, so it’s not obvious the tube would fit into the smaller  28-32 size tires as labeled. It all depends on what you trust: the mold, the tube’s stamp, the box label, or the advertising.

    Next time around, an event I hope (but do not expect) lies far in the future, I’ll spend a bit more for what will undoubtedly be the same tube from the same factory, but from a vendor buying enough QC to ensure the workers know what they’re packing. Having all the labels match would be a definite bonus.

  • Schwalbe Marathon vs. Glass Chips, Yet Again

    We biked to some errands on an unseasonably warm 4 January and, a few days later, I noticed the rear tire on Mary’s bike was flat. A bit of Quality Shop Time later:

    Brown Glass Chip
    Brown Glass Chip

    On the upside, I found it in the garage and fixed it in the basement.

    The chip emerged from one of two adjacent gashes in the middle of the tread, but hadn’t quite cut through the tire. A somewhat larger chip (that’s a 0.1 inch grid) in the other gash cut through the Schwalbe Marathon’s protective belt to puncture the tube, then fell out.

    The rear wheel of her bike now sports a Michelin Pro-Tek Max tube inside a Schwalbe Marathon Plus tire, as does mine. The wheel + tube + tire probably weighs as much as some entire carbon-fiber bikes, but it doesn’t matter.

    Searching for the obvious keywords will produce many other instances…