Posts Tagged Repairs

Mica Compression Capacitor: Unsolderable Pins

The mica compression capacitors have a finish on the pins that turned out to be completely un-solderable:

Mica compression capacitor - solder vs pin

Mica compression capacitor – solder vs pin

Some casual searching suggests this is a problem with sulfur contamination of the tin-lead solder layer. I can’t vouch for any of that, as the flat areas forming the capacitor seem to be silver-plated, but …

After some flailing around, I completely disassembled the capacitor, applied 800 grit sandpaper to remove all of the solder / flux / corrosion / tarnish / surface plating from the pins, dabbed on some RMA flux, then applied a thin layer of solder to both sides. Fortunately, the capacitor could be disassembled; they don’t make ’em like that any more.

The solder layers must be thin, because the slots in the ceramic base must pass two or three pins apiece: four or six solder layers add too much thickness. Solder-wick is my friend!

For reference, the 700 pF side looks like this:

Mica compression capacitor - 700 pF disassembled

Mica compression capacitor – 700 pF disassembled

The steel washer does not have a mica washer underneath (as does the washer on the 400 pF right side). The two grayish steel plates go on the top.

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Improvised Repairs Done Wrong

Mary’s relatives encountered this repair in a rental flat during Thanksgiving week:

Door handle - hex head bolt

Door handle – hex head bolt

Don’t have a hex bolt with the right thread? No problem: just use a sheet-metal screw, perhaps with a self-drilling point:

Door handle - metal screw

Door handle – metal screw

Those hex heads let you apply more torque with less risk of stabbing yourself in the palm, which strikes me as an all-around Good Thing. I prefer socket-head cap screws, myself, but I’ll admit they’re an acquired taste.

I’d like to think I wouldn’t do that …

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Kenmore Progressive Vacuum Tool Adapters: Second Failure

Pretty much as expected, the dust brush nozzle failed again, adjacent to the epoxy repair:

Dust brush adapter - second break

Dust brush adapter – second break

A bit of rummaging turned up some ¾ inch Schedule 40 PVC pipe which, despite the fact that no plumbing measurement corresponds to any physical attribute, had about the right OD to fit inside the adapter’s ID:

Dust brush - PVC reinforcement

Dust brush – PVC reinforcement

The enlarged bore leaves just barely enough space for a few threads around the circumference. Fortunately, the pipe OD is a controlled dimension, because it must fit inside all the molded PVC elbows / tees / caps / whatever.

The pipe ID isn’t a controlled dimension and, given that the walls seemed far too thick for this purpose, I deployed the boring bar:

Dust brush adapter - reinforced tube - boring

Dust brush adapter – reinforced tube – boring

That’s probably too much sticking out of the chuck, but sissy cuts saved the day. The carriage stop keeps the boring bar 1 mm away from the whirling chuck.

Bandsaw it to length and face the ends:

Dust brush adapter - reinforcement

Dust brush adapter – reinforcement

The PVC tube extends from about halfway along the steep taper from the handle fitting out to the end, with the section closest to the handle making the most difference.

Ram it flush with the end:

Dust brush adapter - reinforced tube - detail

Dust brush adapter – reinforced tube – detail

I thought about gluing it in place, but it’s a sufficiently snug press fit that I’m sure it won’t go anywhere.

Natural PETG probably isn’t the right color:

Dust brush adapter - reinforced tube - installed

Dust brush adapter – reinforced tube – installed

Now, let’s see how long that repair lasts …

The OpenSCAD source code as a GitHub Gist:

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Gilmour Garden Hose Y Valve: FAIL

Mary couldn’t unscrew either of the two outlet hoses emerging from one of the (many) Y valves in her Vassar Farms plot. After deploying the Lesser Vise-Grip from my bike toolkit to no avail, I brought a Greater Vise-Grip from the shop and applied brute force. During that process, the plastic inlet hose fitting ripped off the valve and sprayed all but one of its latching teeth across the plot:

Gilmour hose Y valve - inlet fitting

Gilmour hose Y valve – inlet fitting

As it turns out, the male outlet hose fittings on all the metal-body Gilmour Y valves in the plot have corroded:

Gilmour hose Y valve - thread corrosion

Gilmour hose Y valve – thread corrosion

The scarred knurls show the force required to break the brass hose ring loose and unscrew it:

Gilmour hose Y valve - hose interior

Gilmour hose Y valve – hose interior

Some of that crud may be hard water deposits, but the destruction of the male threads seems like a galvanic reaction among all the various metals in play.

The male fitting began rotating in the valve body, so I crushed it in the bench vise to make more headway. While I had the victim clamped down, I hacksawed a slit through the housing, pried back the edges, and freed the parts for one leg of the Y:

Gilmour hose Y valve - parts

Gilmour hose Y valve – parts

You’d think “not corroding” would be high on the list of attributes for a garden hose valve…

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Kitchen Chair Leg Glide

A stick in the ground marking a repair:

Kitchen chair leg glide

Kitchen chair leg glide

The white plastic glide / slide / foot / cap / whatever is molded around a simple nail that broke a divot out of the foot. Fortunately, I caught it before the nail gouged the kitchen floor.

Under normal conditions, I’d replace the foot from my heap, but, my heap having become somewhat depleted, I swapped in another chair, chipped out the broken plastic, undercut the divot, filled it with JB Kwik epoxy, gooshed the foot in place, and taped it until it cured.

We’ll see how long this lasts …

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Hair Dryer Fuzz

Mary reported that her hair dryer didn’t have nearly as much oomph as in the Good Old Days. After a struggle to remove the rear cover (with no affordance to turn in the direction required to release the hidden latches), this appeared:

Hair dryer inlet fuzz

Hair dryer inlet fuzz

One snort from the shop vacuum returned it to the Good Old Days.

That was easy…

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Cropping Images in a PDF

For reasons not relevant here, I had a PDF made from scanned page images with far too much whitespace around the Good Stuff. As with all scanned pages, the margins contain random artifacts that inhibit automagic cropping, so manual intervention was required.

Extract the images as sequentially numbered JPG files:

pdfimages -j mumble.pdf mumble

Experimentally determine how much whitespace to remove, then:

for f in mumble-0??.jpg ; do convert -verbose $f -shave 225x150 ${f%%.*}a.jpg ; done

You could use mogrify to shave the images in-place. However, not modifying the files simplifies the iteration process by always starting with the original images.

Stuff the cropped images back into a PDF:

convert mumble-0??a.jpg mumble-shaved.pdf

Profit!

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