Posts Tagged Repairs

Eroded PTT Cable

While installing new underseat packs (about which, more later) on my Tour Easy, I discovered a bight of PTT cable had been touching the top of the chain:

Eroded PTT cable - Tour Easy

Eroded PTT cable – Tour Easy

The gentle ripples to the right of the worn-through section seem particularly nice; you couldn’t do that deliberately if you had to.

This section of cable should have been taped to the upper frame bars. It’s hidden under the seat, just in front of the rear fender, and between the under-seat packs, so it’s basically invisible from any angle.

Soooo, that probably explains a bit of the intermittent trouble I’d been having with the PTT switch, although most of it came from the corroded switch contacts.

Rather than replace the whole cable, I cut out the eroded section, spliced the conductors, and taped it firmly back on the tubes.

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Tour Easy: Push-to-Talk Switch Rework

The handlebar-mounted PTT button for the amateur radio on my bike once again went toes-up, most like due to the accumlation of road dust and rainwater over the years. Rather than replace the switch, which would require peeling off a massive glob of hot melt glue and resoldering the wires, I just carved the tops off the rivets holding the cover in place, pried off the cover, and removed the button to reveal the top of the switch dome:

Handlebar PTT switch - corroded dome

Handlebar PTT switch – corroded dome

Blech!

The dome flexes outward to contact the (rather crusty) terminals on either side, so all the action happens under the dome.

A lineup of the plastic button, the inverted dome, and the cover plate:

Handlebar PTT switch - components

Handlebar PTT switch – components

The top and bottom of the dome show some grit: that’s where it contacted the switch terminals.

Wiping the crud out of the switch body, scrubulating everything with contact cleaner, and putting it all back together restored the switch to working order. There’s (once again) a snippet of Kapton tape over the cover holding it in place, but I don’t expect this to last very long:

Handlebar PTT switch - kapton cover

Handlebar PTT switch – kapton cover

But it works well enough for now …

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Revlon Tweezers: Bad Spot Welds

Mary bought a pair of Revlon tweezers a while ago, picking a Name Brand to avoid hassles with bottom-dollar crap:

Revlon tweezers - bad spot welds

Revlon tweezers – bad spot welds

Well, that didn’t work.

I contend that the only difference between Name Brands and the bottom-dollar crap I tend to buy is a bit of QC and a lot of price. I’ll agree that’s not strictly true, but it does fit a goodly chunk of the observed data.

Anyhow.

I milled a recess into the corner of some scrap plastic to locate the handle end, then arranged a step block to capture the business end:

Revlon tweezers - drilling setup

Revlon tweezers – drilling setup

That setup ensures the holes go into the corresponding spots on both pieces, because I couldn’t figure out how to clamp them together and drill them both at once. I drilled the other piece with its good side up to align the holes; doing it bad side up would offset the holes if they’re not exactly along the center line.

A closer look:

Revlon tweezers - drilling fixture

Revlon tweezers – drilling fixture

Talk about a precarious grip on the workpiece!

I filed the welds flat before drilling, so the pieces lay flat and didn’t distract the drill.

Then:

  • Center-drill
  • Drill 2-56 clearance
  • Scuff up mating surfaces with coarse sandpaper
  • Apply epoxy
  • Insert screws
  • Add Loctite
  • Tighten nuts to a snug fit
  • Align jaws
  • Tighten nuts
  • Fine-tune jaw alignment
  • Apply mild clamping force to hold jaws together
  • Wait overnight
  • Saw screws and file flush
  • Done!

The clamping step:

Revlon tweezers - epoxy curing

Revlon tweezers – epoxy curing

Those nicely aligned and ground-to-fit jaws were the reason Mary bought this thing in the first place.

The screw heads look OK, in a techie sort of way:

Revlon tweezers - fixed - front

Revlon tweezers – fixed – front

The backside won’t win any awards:

Revlon tweezers - fixed - rear

Revlon tweezers – fixed – rear

But it won’t come apart ever again!

There’s surely a Revlon warranty covering manufacturing defects, printed on the long-discarded packaging, that requires mailing the parts with the original receipt back to some random address at our own expense.

Ptui!

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Bike Helmet Earbud Iteration

Based on having to seal the rear vent hole of the previous earbud, I did the same for the new one:

Earbud - blocked vent

Earbud – blocked vent

The audio quality was terrible, so I tried another bud with a foam windscreen over the hole and a hole punched in the middle of the double-sided white foam tape:

Earbud - foam over vent

Earbud – foam over vent

The audio remained unintelligible, so I tried an upscale (but still cheap, because surplus) Koss earbud, first without blocking the vents and then with snippets of Kapton tape:

Koss earbud - tape over vent

Koss earbud – tape over vent

The earphone has three slits on each side, but only the middle slit has a hole penetrating the case; it must be a stylin’ thing.

That sounded better, so I’ll roll with it. There’s supposed to be a foam cover over the housing, but those things always get grody and fall off; there’s not much point.

As nearly as I can tell, contemporary earbud designs optimize for volume (dBm/mV) and thumpin’ bass, all to the detriment of actual audio quality. Based on numerous samples over the years, there is zero correlation between price (admittedly, on the low end) and audio quality (admittedly, with my crappy hearing).

I own a pair of very nice (and thoroughly obsolete) Shure E2c sound-isolating ear beetles that sound great (even with my crappy hearing), but I’m unwilling to chop them up for the bike headset …

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Easy Reacher Pack: New Elastic Cord

The elastic cord behind the left-side under-seat Easy Reacher pack on my Tour Easy snapped some time ago, probably due to wear against the brace I installed to keep it from flopping around. Quite contrary to what I expected, the repair turned out to be almost trivially easy.

The cord terminates in a pair of plastic lugs, each with a ferrule that slipped off under moderate persuasion to reveal a pair of wedges that engaged the cord:

Easy Reacher pack - elastic cord clamp

Easy Reacher pack – elastic cord clamp

I expected the ferrule to have a positive lock engaging those wedges, but, nope, there’s (at most) a small ridge. Pry the wedges out and the cord slides out of the lug without a protest; the wedges don’t quite meet in the middle with the ferrule in place and there’s plenty of retention force on that flexy cord.

One of the shorter bungie cords in my collection turned out to be exactly the right diameter and length, with ends secured in its hooks using a simple crimped wire. Bending the ends of the wire at right angles freed the cord from its embrace:

Easy Reacher pack - unclamping new elastic cord

Easy Reacher pack – unclamping new elastic cord

The original stainless steel hook lies by the edge of the road along my usual bicycling route, but a slightly reshaped S hook (made, alas, of ordinary steel) fits around the cord well enough. When this one rusts away, I have plenty more.

Insert cord into lugs, push ferrules over locking wedges, remove one ferrule and lug, install reshaped S hook, reinstall lug and ferrule, install new cord on pack:

Easy Reacher pack - new elastic cord

Easy Reacher pack – new elastic cord

Install pack on bike: done!

I have no explanation for how well this worked out; I fear the Universe is saving up spit for something truly awful.

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Image File Recovery Redux

Took a picture of the sewing machine setup with the Sony DSC-F717, transferred it into DigiKam, got the “done transferring, you can disconnect the camera” message, believed it, disconnected the camera, deleted the image file, and then discovered that DigiKam mislaid the image file.

Rather than re-set-up and re-take the shot, I followed my own directions and recovered the image from the Memory Stick:

dmesg | tail
[43176.079853] usb 2-1.6.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[43176.079855] usb 2-1.6.3: Product: Sony PTP
[43176.079856] usb 2-1.6.3: Manufacturer: Sony
[43198.073652] usb 2-1.6.3: USB disconnect, device number 22
[43333.788533] sd 9:0:0:0: [sdc] 1947648 512-byte logical blocks: (997 MB/951 MiB)
[43333.803292] sd 9:0:0:0: [sdc] No Caching mode page found
[43333.803299] sd 9:0:0:0: [sdc] Assuming drive cache: write through
[43333.824681] sd 9:0:0:0: [sdc] No Caching mode page found
[43333.824688] sd 9:0:0:0: [sdc] Assuming drive cache: write through
[43333.825491]  sdc: sdc1
sudo dd if=/dev/sdc of=/tmp/pix.bin bs=1M
^C615+0 records in
614+0 records out
643825664 bytes (644 MB) copied, 38.5841 s, 16.7 MB/s
strings -t x pix.bin | grep Exif | head
  68006 Exif
 208006 Exif
 3f8005 _Exif
 7b8006 Exif
13d8006 Exif
15b0005 wExif
1798005 CExif
19c0006 Exif
1b90006 Exif
1f98005 %Exif
dd if=pix.bin of=image03.jpg bs=$((16#1000)) count=1K skip=$((16#3f8))
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0121431 s, 345 MB/s
display image03.jpg
convert image03.jpg dsc00656.jpg

Obviously, there was a bit more flailing around than you see here, but that’s the gist of the adventure. For what it’s worth, image01 was a random blurred shot and image02 is the ID picture I keep on all my cameras.

The convert step discards all the junk after the end of the image, so the dsc00656.jpg file doesn’t include anything unexpected.

The picture isn’t all that much to look at, even after cropping out the background, but …

Kenmore 158 - stepper drive test

Kenmore 158 – stepper drive test

The advantage of the manual method: renewing one’s acquaintance with tools that come in handy for other tasks.

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Flashlight Switch: Poor Solder Joints

My desk flashlight has three “functions”:

  • 5 UV LEDs
  • 10 white LEDs
  • laser pointer

A four-click rotary pushbutton switch actuates the three functions (plus “off”) in sequence:

Flashlight switch - internal wiring

Flashlight switch – internal wiring

All three lights became intermittent, which suggested a poor return connection at the far end of the battery. The case is, of course, aluminum, with coarse-cut threads that grate as you tighten the parts. I cleaned the crud out of the threads, anointed them with Ox-Gard compound, and discovered that the laser and UV LEDs were still flaky.

Taking the thing apart and unsoldering the switch connections revealed the problem:

Flashlight switch - bad solder joints

Flashlight switch – bad solder joints

Yup, two lousy solder joints. They’re not exactly cold solder joints, because there’s not really a joint there to begin with; the switch tabs never got hot enough to bond with the molten solder before it cooled.

A dab of flux and touch from a hot soldering iron solved that problem.

Assemble in reverse order and it works better than it ever did before!

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