Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
The upstairs baseboard heating loop collected enough air to frustrate the circulator pump, so I had to close the zone shutoff valve and open the drain valve to flush enough water through the plumbing to get the bubbles out:
Furnace zone drain and shutoff valves
Except: turning that little slotted stem required more torque than I was willing to apply. It may have last been turned a decade ago, during the final furnace servicing on record, but we’ll never know its story.
Furnace zone shutoff valve
Three days of dripping Kroil penetrating oil onto the shutoff valve stems and, just in case, their pipe threads, along with applying the maximum torque I was willing to apply, did the trick, albeit with a distressing amount of squeaking.
A hose from the drain valve to the sump pump pit took care of the outgoing water, flushing proceeded uneventfully, a test firing put hot water into the baseboard, and I could declare victory for the oncoming heating season.
Although “chipboard” is also known as “beer mat”, it’s not intended for long-term use under sweaty mugs. After a few weeks of daily use, this is obviously out of spec:
Printed Fragment Coaster – moisture damage
The aforementioned sweaty mug lifted part of a fragment off the coaster:
Printed Fragment Coaster – delamination
The chipboard is Quickboard from Makerstock, which is basically recycled-fiber chipboard with the advantage of being through-dyed in cheerful colors. It’s described as “2 mm-thick, three-layered board” and it looks like the core delaminated from the bottom layer.
Seeing as how it’s near the end of Sweaty Mug season, I smeared Elmer’s Glue Stick PVA adhesive over the fragment, stuck it back in place, and declared victory.
Going back to the original GIMP tracing (storage being cheap, never delete anything), I missed a pixel:
Printed Fragment Set C – GIMP selection – errant pixel
Surely you can see it, particularly because you know exactly where it is. Right?
The (degenerate) path around that pixel becomes a tiny vector in LightBurn:
Printed Fragment Coaster – Set C – orphan vector
It’s easier to see there. Right?
Whereupon LightBurn dutifully punched a pinhole through the chipboard, because that’s what I asked it to do. It also punched that pinhole into the metallized paper reflector under the smashed glass fragment, but I didn’t notice it then, either.
Shrinking the GIMP selection by one pixel width, then growing it by one pixel would eliminate single-pixel selections: just another item on the to-do list while tracing fragments.
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.
The thread passes through the guide hole just below the hex driver in that photo, then through the hole in the needle from the front of the machine. Apparently the 45°-ish angle between those two was large enough to prevent the thread from sliding smoothly along the needle.
Proceeding much as before, but without dismantling the machine cover because I know where the clamp screw will be with the machine shaft at Bottom Dead Center …
The Ruler Foot is now 0.5 mm off the Needle Plate:
HQ Sixteen – Ruler foot clearance – 2
Stacking gauge blocks shows the Needle Bar now sits 0.355 inch above the Plate at BDC:
HQ Sixteen – gage block stack – 2
That is viewed from the right side of the machine, with the button-head screw sticking out of the Presser Bar hidden behind the Needle Bar.
The gauge block set confirming what’s in the stack:
HQ Sixteen – gage blocks used – 2
Then:
Stick a screwdriver through the bottom access hole into the Needle Bar clamp screw
Loosen the Needle Bar clamp screw
Rotate the Needle Bar to put the guide hole exactly in front
Tighten the clamp screw
Verify the shaft is still at Bottom Dead Center
Remove the block stack
Install the Ruler Foot at 0.5 mm
Which looked like this with the shaft at Top Dead Center:
HQ Sixteen – needle bar reoriented – 2
There’s a quilt in progress on the left, so we’ll know if this solved the problem very shortly.
After a rather tedious morning devoted to figuring out why printing had suddenly stopped working, it seems there’s something badly wrong with the most recent CUPS update.
The symptoms included:
Wrong sheet orientation for multi-page output regardless of the Landscape or Portrait setting
No output at all, generally with a CUPS error message
The error messages were utterly inscrutable:
“missing required flags”
“cfFilterChain: pdftopdf (PID 8189) stopped with status 1”
“temp file (object 3 0, offset 11462): dictionary has duplicated key /x12; last occurrence overrides earlier ones”
Downgrading two packages restored the status quo ante:
libcupsfilters 2.2.1-2 → 2.1.1-4
cups 2.4.19-1 → 2.4.16-2
Perhaps cups need not be reverted, but I’m loathe to fiddle around with it now that printing works again.
Those are now frozen in /etc/pacman.conf:
IgnorePkg = cups libcupsfilters
The least-awful way to downgrade / revert packages seems to be with manjaro-downgrade. You can, of course, do it on hard mode with pacman or pamac, but perusing a list of what’s in the update cache helped figure out what just changed.
And there they will sit until the next update rolls through.
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.
