Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
The Shopvac Model 500A (1.25 HP!) inhaling dust from Tiny Bandsaw didn’t start up when I flipped the switch. It had been making horrible noises, but Shopvacs typically sound like they’re on the ragged edge of death, I wear 30 dB earmuffs when it’s running, and that wasn’t the problem anyway.
It turned out the hot (black) wire lead to the motor burned up:
Shopvac motor – charred wire
The neutral (white) wire over on the left side looked just fine:
Shopvac motor – good wire connector
But the hot wire connector was toasted:
Shopvac motor – charred connector
As the connector failed its resistance went up and so did the wire temperature, as shown by the plastic case:
Shopvac motor – melted cover
With barely an inch between the motor armature and the failed connector, this became a zero-Mulligan repair:
Shopvac motor – remaining armature wire
I clipped the failed connector off the wire, very carefully sanded off the burned insulation, then gingerly crimped the business end of a ferrule around the wire + a doubled length of 22 AWG hookup wire:
Shopvac motor – lengthened wire
Doubling the wire brought it up to 19 AWG, a bit larger than the 20 AWG armature wire, and maybe improved its durability. The ferrule surely isn’t rated for this sort of abuse, so I eased some solder into its end in the belief that any amount of solder is a better conductor than a similar amount of air.
Crimp the other end of the hookup wire into the business end of a solderless ring terminal along with the hot wire, anchor the ferrule to (and insulate it from) the armature with a wrap of silicone tape, do the same around the ring terminal, then squirt hot melt glue into the ruined connector housing to keep the wire from flopping around:
Shopvac motor – repaired wire
If it gets hot enough to melt the hot melt glue, there are other problems about to happen.
Reassemble in reverse order and the Shopvac once again makes its on-the-eve-of-destruction whine while inhaling chips.
A slip of tape marked “$5” fell off during this process, reminding me it was a garage sale find from quite a few years ago: saving it from an early grave may be an overall Good Deed.
After 3D printing another set of cap parts, glob the switches into place with tan JB Weld Plastic Bonder:
HQ Sixteen grip cap – switch gluing
More Plastic Bonder joins the cap body to the plug fitting into the handlebars:
HQ Sixteen grip cap – gluing fixture
I laser-cut an acrylic disk to fit the plug stem and hold the bottom of the plug flush with the bottom of the cap, with the PTFE fabric preventing inadvertent bonding of All The Things. It’s perched atop an empty thread cone to cure: quilting requires a lot of thread and I have a good stock of cones.
The button cap body solid model now includes alignment marks to eliminate the need for the bench block & clamps:
HQ Sixteen grip cap – alignment marks
Soldering the cable directly to the switch terminals is déclassé, but the collar prevents the cable from exerting any force on them:
HQ Sixteen grip cap – wiring
This time around, dabs of hot-melt glue hold the faceplate to the cap body.
I also used hot-melt glue to stick the transparent cover onto the handlebar body, as the OEM sticky tape was losing its mojo:
HQ Sixteen grip cap – wiring closeout
The rightmost three LEDs went dark a while ago and, while I had everything apart, I tracked the failure to the third LED from the right, replaced it, and it’s all good again. Those LEDs (plus the side groups) still can’t hold a candle to the Nose Ring Lights and Under-arm Lights, but it’s good to have all the lights working.
I managed to break one tiny wire on the header (wrapped in black silicone tape next to the IC on the right) joining the two cables from the control caps, but other than that things went smoothly.
Now I can start on other long-awaited tweaks before the next quilt arrives.
Which is a little more than a year after I built it, so I’m not red-hot pleased with the switch reliability. On the other paw, Mary has done a lot of quilting in the last year, generally controlling the machine with her left thumb, so that particular button has gotten a lot of use.
Because I glued the caps together, rather than trying to hide screws in finger-friendly locations, the replaceable unit is the whole cap.
I originally cut the cap labels using LightBurn’s Print-and-Cut tool to align the laser to the printed label, but subsequent experience making punched cards showed it’s generally easier (at least for my simple projects) to skootch the layout to match the laser position at known features:
HQ Sixteen control caps – laser alignment
Those small magnets hold the laminated label flat against the honeycomb.
The Position Laser tool puts the laser at a selected corner of the square, with Object Snap ensuring it’s really at the corner. Firing a test pulse to verify the red-dot pointer is aligned with the focused CO₂ laser spot is good practice.
Unlike the cards, the control caps don’t have fractional-millimeter tolerances, so, after verifying the printed label alignment at all four outer corners, it’s Close Enough™:
HQ Sixteen control caps – label cut
Cutting the adhesive sheet posed no alignment problems:
Replacing the drying fan didn’t prevent the Samsung dishwasher from crashing when the drying cycle starts, so I eventually figured out how to run the “Smart Install” test sequence:
Samsung Dishwasher – DW80K7050US – p 37 – Service Test Mode
Which ticked through everything right up to the start of the “Check Drying” step:
Samsung Dishwasher – DW80K7050US – p 39 – Check Drying
Whereupon all the control panel LEDs went dark and a little red status LED on the PCB began blinking what must be an error code: long / pause / long-short-short. Of course, I cannot find any doc for that LED’s code.
The “Auto Door Open Actuator” is a wax motor, a device I had never encountered before. It opens the door through a whippletree pushing two tabs against the door:
Samsung dishwasher – door auto-open mechanism
The meter measures the voltage across the wax motor Auto Door Open Actuator through improvised widowmaker jumpers jammed onto the quick-disconnect fittings. As you might expect, the meter showed 000 VAC before, during, and after the crash, suggesting something is wrong with the relay intended to activate the motor.
Because the test sequence activates the drying fan after opening the door, the fan never even twitched.
For twelve bucks (spend up to $150 if you prefer), I had a generic DD66-00089A actuator in hand before dragging the dishwasher out of its lair and, being me, had to measure what it did:
Samsung Dishwasher – Door Actuator wax motor – test layout
It’s about 1.8 kΩ across the terminals and, not being fussy about its input voltage, will dissipate anywhere from 6 to 32 W in operation. Because the “motor” works by the force generated by expanding liquid wax, the response time obviously goes down as the voltage goes up.
After a few cycles to figure things out, plotting elapsed time against piston displacement is surprisingly linear right out to the 6.5-ish mm maximum stroke:
Wax Motor – time vs. displacement
It take much longer from a cold start, which is how it’s normally used, so the 30 s intercept at 0 mm is definitely on the low side.
Samsung no longer manufactures the DD82-01337A7050 control board, the usual aftermarket suppliers report it’s out of stock, and, given the lack of doc, I am loathe to pull it out of the dishwasher for failure analysis / repair. The one-hour cycle gets the dishes clean and a 46 minute countdown timer reminds me to open the door for drying, so the failure seems survivable for the immediate future.
A three-LED string in the central control panel of the front handlebars has gone dark a year-and-a-half after I replaced all of them. Of course, that’s what I get for using new-old-stock surplus parts, but … the COB LEDs in the nose ring lights are still going strong, so there’s plenty of light where it matters.
The star pattern on the ceiling (lower right) comes from sunlight reflecting off one of the salvaged star quilting rulers. I think the oblong patterns (upper left) come from other rulers.
The upper five-LED string in the middle module failed open-circuit, which left the remaining two strings handling too much current. The five LEDs across the middle look like they’re running at War Emergency Power and the lower five are limping along:
COB LED failure – detail
The dark spots in the middle are overexposed pixels.
I soldered in a replacement from the same bag and it’s all good again, but I expect that won’t last very long.
A friend with declining hearing asked for my experiences with the Nuheara IQbuds² MAX I’ve been re-batterying for quite some years:
Nuheara IQBudsMax2 – battery replacement
Given that other folks may have the same issue, herewith a lightly edited version of the email I sent:
Do you use conventional hearing aids?
Nope, because when I was looking around, maybe six years ago, dropping $500 on Nuheara rather than $5000 on real hearing aids seemed like a good first step. Five Benjamins would be lost in the roundoff should I get something seriously exceedingly much more definitely better.
They are now $200 from Amazon. Nuheara had licensed the design to HP and stopped selling them in the US, which is what you’ll find on their website, so maybe the Amazon seller isn’t entirely legit.
My decision was partially based on an audiologist measuring my ears and stating my loss was “not aidable”, which meant it wasn’t severe enough to justify hearing aids. I interpreted that to mean her experience with similar folks showed insufficient return for the sales effort involved.
Before OTC hearing aids were legit, Nuheara was rated very near the top of the “not really hearing a hearing aid” pack. The better ones cost about half the price of real hearing aids, so IMO it was the best cost-performer.
Every time the question has come up since then, the crux is “Would real hearing aids be that much better than the Nuheara buds” and the answer has been “Nope”.
I’ve done occasional test sessions with various “hearing instrument specialists” and the results show I have essentially no hearing above 1 kHz, thus reducing female voices to mumbles. They are unwilling to test my hearing while wearing the Nuheara buds, for obvious reasons.
Do you use Nuheara instead?
Pretty much whenever Mary is around, because that’s the only way I’ll understand what she’s saying unless we’re face-to-face in the same room.
The noise reduction (see below) works wonderfully well in the car, eliminating all the road noise and isolating her voice.
experience and any advice
Unlike simple “personal sound amplifiers”, Nuheara has a six-band equalizer with settings based on an automated “Tap when you hear the tone” test done in the app. It does not, much to my frustration, display a line graph or export the numbers, but the circular diagram shows I don’t have much hearing above the lowest two channels:
Nuheara Ear ID – 2026-0811
I think the lower quarter of each side the rings is cosmetic filler, given the silence I hear when the test is surely presenting the higher frequency tones. If there’s a lower score than what I get, I cannot imagine what it might be for.
The buds have a high/low cut filter to reduce background sounds that works wonderfully on the ubiquitous 120 Hz hum anywhere in North America. I obviously don’t have much use for the high-cut filter setting.
The “Speech in Noise Control” applies DSP magic to reduce general background sound and emphasize speech, which is more complex than a simple frequency filter: SINC is astonishingly effective. What comes through the DSP magic isn’t audiophile quality, but it’s comprehensible and that’s what counts.
The downside: I hear nothing other than speech while it’s engaged. When we have supper on the screened porch, there is no background sound other than occasional traffic until I disable the filter and SINC, whereupon I can hear the breeze rustle the leaves / birds chirping / Vassar carillon chimes / stuff like that. Fair tradeoff, IMO.
The DSP monitors ambient sound and adjusts the overall gain to reduce the in-ear volume. My normal settings turn the water stream from the kitchen faucet into deafening white noise, but the gain drops after a few seconds and I’m effectively deaf. This also applies when we’re walking outdoors, with any wind noise in the microphones turning the gain down enough that I hear just as poorly with the buds as I do without them.
The buds can stream audio from the phone and the equalizer applies to phone calls / music / whatever. Real hearing aids tend to not stream audio, because Bluetooth requires bigger batteries. Getting phone calls with adjusted audio in both ears is wonderful.
The buds also have “tap” controls to start / stop streaming, raise / lower volume, and (most importantly) enable / disable “world audio” = I can mute the sound before I start doing something noisy. The “world off” = active noise cancellation isn’t perfect, but it’s Good Enough for most purposes.
I wear them under Peltor 28 dB hearing protectors (which cost 25 bucks two years ago sold by Amazon, so beware scalpers) while mowing: the muffs knock down all sounds and the buds remove what’s left. I can then stream music at reasonable volume to make mowing easier.
Those big batteries make the buds heavy in the ear, but it seems the same batteries appear in audio-only buds, so they may be the smallest ones that get the job done.
A good ear canal seal is essential and I’ve gone through several different “brands” on Amazon before finding effective foam tips.
Bottom line: I have no experience with their competition, but the Nuheara buds do everything I have ever read other buds / real hearing aids can do. Color me satisfied.
