Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
For reasons not relevant here, I was called upon to open a bulletin-board lock with a complete lack of keys:
Bulletin Board Lock – locked
It’s obviously not the highest security lock you’ve ever seen. Armed with a small screwdriver and an old darning needle, this took the better part of 30 seconds:
Bulletin Board Lock – opened
Actually, I devoted a few minutes to verify none of my collection of random keys would suffice.
Replacing the lock not being within my remit, I improvised a simple retainer from available materials:
Bulletin Board Lock – improvised strap retainer – front
Yes, the nylon cable tie will surely pull out of the latch:
Bulletin Board Lock – improvised strap retainer
And I admit the installation’s security has taken a definite downward step:
Bulletin Board Lock – push pin security
Some day, I’ll tote a wrench to the site, remove the lock, and improve the improvisation.
Replacing the lock seems mired in an intractable budgetary wrangle. Similar locks being five bucks on Amazon, I’m tempted to just make it happen, but doing so would apparently roil the decision-making stratum. I’m perfectly happy to remain an on-call techie devoid of political ambition.
We have, as you might expect, a Favorite Cheese Slicer of no particular provenance. Being made of cheap pot metal, it left black smudges wherever it went and, decades ago, I coated it with bright red rubbery grip material. Recently, the coating became lumpy and peeling off the loose sections revealed a definite problem:
Cheese slicer – aluminum corrosion
Vigorous scrubbing with a foam sanding block and a Scotchbrite pad, interspersed with rotary wire brushing, removed the corrosion and left a slightly pitted metal frame. Protip: scrub under water and wire-brush with a vacuum hose to keep the dust under control.
A pair of 6-32 screws, nuts, and brass sleeves, with two oil dots protecting the frame threads, provided hand grips while I wiped it down with denatured alcohol and coated it with XTC-3D epoxy:
Cheese slicer – epoxy curing
Turns out the mixing stick worked quite well to cover the entire thing, as the epoxy does a great job of leveling itself. I suppose wasting a tiny brush would be more professional, but …
It quietly dripped excess epoxy into a strategically placed trash can for about ten minutes. I wiped off the final drip before the epoxy solidified, leaving a smooth layer over the end of the handle:
Cheese slicer – reassembled
It’s back in service and works as well as ever, with a handle now smooth to the touch. I suppose I could have tinted the epoxy to hide the metal, but we regard those corrosion pits as beausage.
I’ve slathered XTC-3D on some3D printed parts, but have no idea how durable it is; this should serve as an accelerated survival test under rather harsh usage.
The instruction sheet says XTC-3D isn’t the most transparent epoxy they make and, indeed, the layer left in the mixing pan came out more hazy than I expected:
XTC-3D Epoxy – thin cured layer
They point out the haze doesn’t matter for thin surface coatings, which is certainly true.
The general idea is to wrap a new bracket around the old bracket, because trying to remove the old one will probably cause more damage:
Refrigerator shelf slide – trial assembly
A pair of screws hold the new bracket to the shelf support:
Refrigerator shelf slide – support screw nut openings
Those two screws must support the entire weight of the drawer, which is exactly what broke the original all-plastic frame and slide.
The epoxy chip and transparent plastic sheet in the first picture spaced the old aluminum bracket away from the shelf support and reduced the space beyond the new bracket enough to require drilling access holes. Fortunately, they’re hidden inside the support frame, so nobody will ever know.
The shelf support is a huge floppy rectangle, so I clamped it to the bench vise while drilling the holes:
Refrigerator shelf slide – upright vise clamp
The new bracket is on the right, with a sheet of white acrylic spacing it away from the shelf support by exactly the same distance as the angled aluminum snippet replacing the failed epoxy & plastic on the broken part:
Refrigerator shelf slide – bracket parts
The two holes in the middle of the aluminum parts show that I used exactly the same angle brackets as raw material. It’ll be a sad day when I eventually use the last of those brackets.
Putting the parts together, with double-stick tape holding all the parts in place, shows how they fit:
Refrigerator shelf slide – repair trial assembly
And then it just snapped into place. I didn’t bother pretending solvent glue would help anything, nor did I apply any epoxy, so this whole thing hangs from those two 4-40 screws. On the other paw, their steel beats the original white plastic.
I devoutly hope to never rebuild the actual drawer slide, but these dimensions may help somebody else out of a jam:
Refrigerator shelf slide – dimensions
The vertical “40” dimension refers to the available space from the bottom of the white plastic part to the top of the shelf support frame; the new bracket is a tad shorter than that.
The plastic parts in that refrigerator have been a complete disappointment: were it not for my relentless repair jones, we’d likely be on our third or fourth refrigerator by now. Oddly, the cooling parts continue to chug along (*), without more than the occasional loud noise in the middle of the night.
We’re definitely doing our part to reduce our waste stream.
I eventually noticed the yellow LED indicating +24 V input from the power supply (previously, a noisy wall wart) was dark. Poking around revealed I’d inadvertently installed a 1 kΩ ballast resistor:
LF Preamp – burned power-on LED resistor
A 1/4 W resistor can’t dissipate half a watt for very long, as shown by the discolored circuit board around the leads and the faint smell of electrical death in the area.
I swapped in a 3.3 kΩ resistor, the yellow LED lit up for a few seconds, then went dark again. This time, the LED was dead; apparently, it’d been overstressed for long enough to fail. I can’t be too annoyed.
Unfortunately, replacing the LED required removing the entire housing with all three LEDs, chopping off the defunct block, reinstalling the attenuated block with the two green LEDs, installing a similar red LED, and finally installing a nice 3.3 kΩ half-watt resistor:
That’s with the scope probe ground clip connected to the wall wart coax connector barrel and the scope probe tip on the ground clip. It’s not the noise on the 24 VDC supply, it’s the noise injected into the ground connection!
Huh. Makes it tough to sort out low-level signals, it does indeed.
Consider one of my bench power supplies at 24 V:
Ground noise – bench supply 24 V – probe on gnd lug
Nice & quiet, the way power should be. One might quibble about the residual noise, but at least it’s not blasting out horrific bursts at 120 Hz.
“High Quality Commercial Grade” my aching eyeballs.
[Update: Edits based on eagle-eyed observations in the comments. ]
Not as many missing components as I expected, though, if the truth be told. The missing transformer common-mode choke seems odd and, AFAICT, the resistor inductor angling out from the R1 callout doesn’t connect to anything, connects directly to the AC line because C5 is missing and the pad joining them doesn’t go anywhere else it replaces the jumper (?) to the bottom-left pad and the missing parts. The red LED in the upper right isn’t visible through the black case, although it might serve as a voltage regulator.
Over on the far right, beyond the transformer and between the two capacitor cans, is a component marked C9 with an oddly angled part. Seen from the other end, it’s a ferrite bead:
SMAKN 24 VDC wart – output ferrite
I don’t know why that spot has an inductor symbol with a capacitor part callout.
The other side of the PCB looks clean:
SMAKN 24 VDC wart – PCB solder side
It’ll probably serve well in a noise-tolerant application, maybe an LED power supply.
As pointed out in the comments, there’s a UL mark:
SMAKN 24 VDC wart – label
Not sure what I’ll replace it with, although a small 24 V power supply brick may suffice.
This notification appeared every day after I got my shiny-new / soon-to-be-obsolete Google Pixel XL:
Screenshot_20170906-085931 – Update Your Phone Number – detail
Fast-forward through nearly a month of doing the obvious things to no avail:
Tap the notification to update my phone number
Update my phone number from Firefox on the Pixel
Update my phone number from Firefox on my desktop
Ditto, from Chromium
Just dismiss the notification, repeatedly
Change my phone number in various Google places
Ditto, in various ways
Searching on the obvious keywords provided very few hits and none with a resolution. I followed one suggestion to flush the Google Play and Google Play Services caches, to no visible effect.
So I started a chat with Google Support by coredumping the entire list of Things Already Tried. After ten minutes of pleasantries, mostly spent idling while Holmes (great name for a tech support guy) read my coredump (and, most likely, timeshared a dozen other support chats), this transpired:
The “troubleshooting steps” look like a generic list of progressively more desperate measures applicable to any mysterious Android problem:
Clear app data for the Play Store
Go to Settings > Apps.
Tap Google Play Store > Storage > Clear data > Ok.
At the top left, tap the Back arrow to go to the “App info” screen.
At the top right, tap More (3 dots) > Uninstall updates > Ok > Ok to restore the app to its factory version.
Note: The Play Store will update automatically within 48 hours. If “Uninstall updates” is dimmed, you can skip this step.
Note: If you’ve changed the Google Play Store app settings (content filters, password protection, etc.), you’ll need to set them up again.
Clear the app data of Google Play services
Warning: Clearing the app data of Google Play services can reset settings, affect app performance, and cause unpredictable behavior across the device.
Go to Settings > Apps or Application Manager.
At the top right, tap More (3 dots) > Show system apps (on Android versions lower than 6.0, go to All instead).
Tap Google Play services.
Note: If you don’t see “Google Play services,” check Show all system apps and make sure that both Google Play Framework and Google Play Services are enabled. If they aren’t enabled, download the Google Play Service from Play Store.
Tap Storage > Clear cache.
Then tap Manage Space > Clear All Data > Ok.
After completing this step, you should check the settings on your apps to see if they’re still configured correctly.
Remove and re-add your Google Account
Note: This may reset settings and remove in-app content. However, your purchases and synced data (Gmail, Google contacts, etc.) are tied to your account and will be available after re-adding your account.
Go to Settings > Accounts > Google.
Tap the name of the account you wish to remove.
Important: Make sure you remember your account password. You’ll need it to sign back in to your account.
At the top right, tap More (3 dots) > Remove account > Remove account.
At the top left, tap the Back arrow > Add account > Google.
Sign in to your Google Account.
Uninstall and reinstall Play Store updates
Temporarily uninstalling updates to the Google Play Store app can help fix some issues.
To revert the Play Store app to the previous version:
Go to Settings.
Tap Apps or Application manager (depending on the device).
Tap Google Play Store (depending on the device, you may need to go to All).
Tap on the menu button, and then Uninstall updates.
If the Uninstall updates button isn’t available, skip the rest of this step and continue troubleshooting.
When prompted to change the Play Store app back to the factory version, tap OK.
Go back to the device’s home screen and relaunch the Play Store. Your Play Store app should update to the latest version within a few minutes.
If the Play Store app doesn’t update, tap on the menu button from within the app and go to Settings. Scroll down until you see Play Store Version. Tap on that to check for an update. If none is available, continue to the next step.
Uninstall updates for Google Play Services
Go to Settings.
Tap Apps or Application manager (depending on the device).
Tap Google Play Services (depending on the device, you may need to go to All).
Tap on the menu button, and then Uninstall updates.
If the Uninstall updates button isn’t available, skip the rest of this step and continue troubleshooting.
When prompted to change the Play Store app back to the factory version, tap OK.
Reset your device to factory settings
If you’d like help with resetting your device, contact us from another device and we’ll walk you through it.
To reset your device:
If you have an SD card, remove it to save the data on the card.
Reset your Android device to factory settings.
Sign in to your device with a Google Account that was signed in before the reset.
If you removed an SD card, reinsert it.
To reload your apps and data:
Open the Play Store app.
Tap the Menu (3 lines) > My apps & games > Library.
Next to the apps that you’d like to install, tap Install or Enable.
If the issue still persist after performing all the troubleshooting steps I request you to reply to this email with the screenshot.
As it turned out, blowing away “the app data of the Google Play services” did the trick; the notification Went Away and hasn’t returned.
A thin plastic wrench is absolutely no good for torquing down the locknut, but that’s not what it’s for. Adjust the bearing race to the proper preload with this wrench, hold it in place, then torque the locknut with the BFW.
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Now, I’d like to say that was easy, but in actual point of fact …
First, I forgot to divide by cos(180/6) to convert the across-the-flats size to the diameter of OpenSCAD’s circumscribed hexagon-as-circle, which made the wrench uselessly small:
Tour Easy Headset Wrench – v1
If you have a 28 mm nut with low torque requirements, though, I’ve got your back.
While I had the hood up, I slenderized the handle into a much shapelier figure:
Tour Easy Headset Wrench
Trotting off to the garage with a warm plastic wrench in hand, I discovered the blindingly obvious fact that the headset nuts have eight sides. On the upside, the number of sides became a parameter, so, should you happen to need a five-sided wrench (perhaps on Mars), you can have one.
The Smell of Molten Projects in the Morning 