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.
If it used to work, it can work again
Ordered 100 stainless steel M3 washers from a “US Seller”, received this:
Yeah, it looked a bit short to me, too.
The chopped and bent washers in the upper right corner suggest the seller got floor sweepings from his source, which is about what you’d expect for a bottom-dollar vendor.
The seller refunded half, which wasn’t particularly generous, but I wasn’t ready to go to the mat for two bucks.
A pair of colorful laser-cut stacked acrylic Raspberry Pi cases with “Moster” (*) heatsinks arrived, with the intent of dressing up the HP 7475A plotters for their next Show-n-Tell:
Unfortunately, the thermal tape on one of the CPU heatsinks was sufficiently wrinkled to prevent good contact with the CPU:
The seller sent a replacement copper slug with tape on one side. Presumably, they glue it to the heatsink with thermal silicone:
Of which, I have none on hand.
So I did what I should have done originally, which was to drop a few bucks on a lifetime supply of thermally conductive heatsink tape, apply it to the bare side of the slug and stick the slug to the heatsink with their tape:
The blue stuff is the separation film, with the tape being white. It doesn’t match the black tape on the other side, but seems gooey enough to work.
Done!
Despite the heatsink hype, ball grid array chips dissipate most of their heat through their pads (and perhaps a central thermal pad) into the PCB, so sticking a heatsink atop the package is largely decorative, along the lines of hotrod ornamentation.
The epoxy packages used in previous Raspberry Pi iterations had better thermal conductivity to their top surface:
Than the more recent metal-top packages, which surely have inert-gas fill under the lid:
Pix cropped after being pilfered from the Official Raspberry Pi site.
Yes, the heatsink does conduct some heat into the air, even if not nearly as much as you might want.
(*) I’m pretty sure “Moster” was a typo in the original eBay listing which took on a life of its own to become something of an unofficial trademark. All of the search results ship from Duluth, Georgia (USA), regardless of the nominal seller; feel free to draw your own conclusions.
After about a month, a replacement for the fallen utility pole arrived:
This is much easier than digging a hole by hand:
Verily, given the right tools, any job becomes do-able:
It was fascinating for me and just another day at the office for everybody else:
They nailed the original pole tag to the new pole, complete with the original 1940 nail:
I expect this pole will outlive me, just as the original pole outlived the folks who built our house.
The most memorable comment came from the person doing the CHG&E damage assessment, who really really wanted this to not be their problem: “Anybody could steal a pole tag and nail it on that pole.” I asked what location their records showed for the pole tag, whereupon the conversation moved on.
Second-place award: no, we were not interested in trenching underground lines 300 feet along the property line, at our expense, to avoid an “unsightly” pole.
For unknown reasons, I was supposed to figure out which telecom utilities had wired the pole, notify them, and wait for them to tack their cables to the new pole. I called both Verizon and Altice / Optimum, got service tickets, and watched them close the tickets without further action. I tried re-opening the Verizon ticket and was told somebody would be there within 48 hours. An Optimum guy showed up, promised a quick return visit from a team with proper equipment, but nothing happened.
I suppose having no customer at the end of the cable removed any motivation to clear their hardware off our lawn, so, after two weeks, I deployed the bolt cutter, rolled up the cables, and scrapped ’em out.
Done!
After a few days of topping off the rear tire on Mary’s bike, with no gashes or debris in the tire, I finally replaced the Michelin Protek tube and autopsied it:
While it’s possible to extract the valve and perhaps even clean / replace it, I think that’s just delaying the inevitable. The rubber shreds may be necessary to fill large punctures, but they seem to wreck the valve seal.
Her bike now has an ordinary (pronounced “cheap”) tube inside the Schwalbe Marathon Plus armored tire. We’ll see how long this lasts.
The Raspberry Pi running the MPCNC recently seized up with baffling symptoms, which generally indicates the poor little MicroSD card serving as a “hard disk” has failed:
I managed to open a terminal emulator, whereupon all of the non-built-in shell commands couldn’t be found.
Proceed as before: binary-copy the entire MicroSD card to another one, pop it in the RPi, and it’s all good again.
For the record, the new card is an unused Samsung Evo Plus. I do not understand the difference between the “Evo Plus” and “Evo+” branding, other than to suspect one of being a very good fake.
In round numbers, MicroSD cards seem to last a year under what seems like not-too-demanding service; I’m not running the MPCNC all day, every day.
So this happened when I grabbed an alligator clip lead:
My coax cable and clip lead collection includes everything from “I’ve had it forever” to “Recent cheap crap”, including much of Mad Phil’s collection. Some of the recent crap included Chinese clip leads with what can charitably be described as marginal connections:
The insulation may provide some compliance in the crimp, but the alligator clip itself consists of cheap steel which won’t hold a crimp, even if it was crimped firmly to start with.
As a rule, the crimps aren’t particularly good:
The most obvious effect is high end-to-end resistance:
Yes, yes, 122 Ω in an alligator clip lead is high.
The test setup isn’t particularly intricate:
The lackadaisical crimps also have unstable resistances:
So I figured I may as well repair the lot of ’em.
I stripped the lead back to expose fresh copper, soldered it to the clip, then re-crimped the clip around the insulation for some token strain relief:
I won’t win any soldering awards, but the resistance is way better than before:
If more than half an ohm seems a tad high for a foot of copper wire, you’re right. My slightly magnetized bench screwdriver shows it’s not copper wire:
I’d say it’s copper-plated steel, wouldn’t you?
Those of long memory will recall the non-standard ribbon cable I used as a 60 kHz loop antenna. In this case, the Chinese manufacturer figured nobody would notice or, likely, care. Given the crappy overall quality of the end product, it’s a fair assumption.
I was mildly tempted to replace the wire with good silicone-insulated copper, but came to my senses; those “high voltage” silicone test leads will be Good Enough for higher-current connections.
While I was at it, I pulled apart my entire collection just to see what was inside and fix the ailing ones. These clips date back to the dawn of time, with what started as excellent crimps:
Alas, after I-don’t-know-how-many decades, they’re not longer gas-tight, so I soaked a dollop of solder into each one:
Chekkitout: “Made In Japan”.
Someone, perhaps me wearing a younger man’s clothes or, less likely, Mad Phil in a hurry, solved a similar problem with bigger blobs and no strain relief:
So, now I have a slightly better collection of crappy alligator clip leads. The copper-plated steel wires will eventually fail, but it should become obvious when they do.
Test your clip leads today!
The bathroom drain rod slipped out of the pop-up stopper, giving me the opportunity to see how well it’s surviving:
After not quite two years, it’s not obviously rotting away.
Life is good …
