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.

Tag: Repairs

If it used to work, it can work again

Ooma Telo 2: Speaker FAIL

The tiny voice inside our Ooma Telo 2 box died, although the VOIP phone service continued to work fine. A bit of searching showed the speaker seems to be the weak link.

Well, I can fix that.

Start by prying the recessed top panel off the case:

Ooma Telo 2 – upper case latches

Remove the circuit board to expose the tiny speaker, taking care not to rip the tiny wires out of the tiny connector:

Ooma Telo 2 – OEM speaker to PCB

You can’t measure a dead speaker, but it seems to be an 8 Ω unit.

The speaker sits in a rubber surround, with a foam rubber cushion against the PCB, tucked into a walled garden stiffening the case:

Ooma Telo 2 – speaker port

I don’t happen to have a tiny 8 Ω speaker, but I do have a bunch of small speakers (Update: 28 mm OD), so I bulldozed those walls with a flush cutting pliers and a bit of cussing to make room:

Ooma Telo 2 – modified speaker port

Nibble an adapter ring to match the rim of the new speaker, thereby routing the sound out those little holes, and hot-melt glue it in place:

Ooma Telo 2 – speaker adapter

Hot-melt glue the new speaker in place atop the adapter, taking care to fill all the edges / cracks / crevices below it with an impenetrable wall of glop:

Ooma Telo 2 – replacement speaker installed

The sealing part turns out to be critical with these little speakers, because a leak from front to back will pretty much cancel all the sound from the cone.

Cut the wires off the old speaker, affix to the new one, replace the PCB, snap the case lid in place, and it sounds better than new.

Millions of transistors in those ICs, but Ooma can’t spec a good speaker? Maybe they should have used a bigger speaker to begin with; ya never know.

2019-06-26
Dell U2711 Monitor: FAIL

My landscape monitor, a six-year-old Dell U2711, died after a few days of flickering and failure-to-start. As you’d expect with any old electronics, particularly from Dell, it’s the electrolytic caps:

Dell U2711 Monitor – failed caps

All of the black-cased caps on the board had bulged cases:

Dell U2711 Monitor – failed FOAI cap – detail

They’re (allegedly) made by FOAI, for whatever that’s worth.

They’re not really capacitors any more:

Dell U2711 Monitor – 100 uF 5 ohm cap

I replaced all of them with cheap eBay caps to no avail. Spot-checking the other (“brown”) caps on the logic board showed they were still good, but the power supply board is firmly glued in place and I can’t get to the HV cap.

A new monitor arrived two days later and it’s all good again.

2019-06-25
Primitive Screwheads

Painting the patio railing required removing the short section on the garage, which stalled with a thoroughly galled / corroded nut on the 2 inch bolt going through the wall. Deploying a Dremel slitting wheel and bashing the slit open with a cold chisel saved the day, as shown in this staged reenactment:

Patio railing – square head bolt – extraction

It seems square head bolts have gone out of fashion, at least in the 3/8-16 size seen here, over the last half century:

Patio railing – square head bolts

I reused the lag screw with no qualms at all.

The local fastener emporium had square bolts ranging upward from 3/4-10, which wasn’t much help. Amazon has ’em, if you spend enough time rummaging around in the debris from its search engine, at a buck apiece in lots of ten. Fortunately, a local big-box home repair store had 3/8-16 hex head steel bolts and square nuts, so I needn’t start from scratch.

Start by turning off the hex head:

Patio railing – square head bolt – removing hex head

Thread the end, starting in the lathe and ending with a die turned just barely enough to accept the nut:

Patio railing – square head bolt – threading

Epoxy the nut in place and sand it to rough up the surface finish enough to hold the primer:

Patio railing – square head bolt – lineup

Yeah, that’s a nasty little zit. Fortunately, nobody will ever notice.

Prime & paint the railing, affix it to the garage wall, then prime & paint the bolt:

Patio railing – square head bolt – installed

Thing looks like it grew there; tell nobody about the zit.

The yellow blotches decorating the shiny black paint come from the pine trees across the driveway. The first day of pine pollen season corresponded to the second day I intended to paint; the dust clouds were a wonder to behold.

Bonus Quality Shop Time!

The far end of the railing around the patio has a bracket against the house siding with a hole intended for a 1/4 inch bolt they never installed, perhaps because there’s no way to maneuver a bolt into the space available.

The threads on the 3/8-16 bolt may be wrecked, but turning the shank down to 1/4 inch isn’t any big deal:

Patio railing – fake bolt – thinning shank

Part off the head with a stub just long enough to fit into the bracket, epoxy that sucker into the hole, and paint it black:

Patio railing – fake bolt – installed

The square post on the left goes down to an anchor in the concrete patio, the railing is welded to a 4 inch column a foot away, and the end of the railing isn’t going anywhere; the fake bolt is purely for show.

And, yes, the dust atop the railing is more pollen from the pine trees responsible for the weird green-yellow reflections on the vertical surfaces.

No boomstick required!

2019-06-24

Kitchen Blender Base Spacer

We don’t use the blender much, so the most recent bearing replacement continues to work. I never got around to re-making the overly long shaft spacer from the first bearing replacement, which I compensated for with a spacer kludge cut from a random chunk of bendy plastic sheet.

Which we put up with For. Eleven. Years.

The blender recently emerged from hiding and, with my solid modeling-fu cranked up to a dangerous chattering whine, I conjured a real spacer:

Blender base spacer - Slic3r preview — Blender base spacer – Slic3r preview

It pretty much disappears into the blender base, which is the whole point of the operation:

Blender base spacer - installed — Blender base spacer – installed

When the bearings fail again, I promise to make a proper shaft spacer and toss this bodge.

The OpenSCAD code as a GitHub Gist:

	// Kitchen blender base adapter
	// Ed Nisley KE4ZNU June 2019

	//- Extrusion parameters must match reality!

	/* [Hidden] */

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	ID = 0;
	OD = 1;
	LENGTH = 2;

	//———-
	// Just build it

	Spacer = [48.0,66.0,1.8]; // LENGTH raises blade holder
	Aligner = [Spacer[ID],52.0,Spacer[LENGTH] + 3.0]; // LENGTH locks into base ring

	NumSides = 434;

	//———-
	// Just build it

	difference() {
	union() {
	cylinder(d=Spacer[OD],h=IntegerMultiple(Spacer[LENGTH],ThreadThick),$fn=NumSides);
	cylinder(d=Aligner[OD],h=Aligner[LENGTH],$fn=NumSides);
	}
	translate([0,0,-Protrusion])
	cylinder(d=Spacer[ID],h=10*Aligner[LENGTH],$fn=NumSides);
	}

view raw Blender base spacer.scad hosted with ❤ by GitHub

Not that it really deserves so much attention …

2019-06-21

Dryer Vent Adapter Rebuild

When we bought this house, it had its original clothes dryer, which was vented directly through the wall with a few inches of 3×10 inch square duct. Alas, contemporary dryers use 4 inch round hoses, so I conjured a round-to-square adapter from a length of air handler duct:

Dryer Vent – end view

I’d used … wait for it … duct tape to hold the end caps on, because I knew I’d be taking it apart to clean out the fuzz every now & again. The most recent cleanout occurred when I noticed the end cap had eased its way out of the adapter, releasing warm fuzzy air behind the dryer.

The solution, which I should have done decades ago, holds the end caps in place with sheet metal screws:

Dryer Vent – screws installed

A pair of small clamps held everything in the proper location while I applied a suitable step drill and installed the screw:

Dryer Vent – screw clamps

Now the duct tape just seals the gaps, rather than holding against the minimal pressure in the box, and it should be all good until the next cleanout.

So simple I should’a done it decades ago. Right?

2019-06-20
Hearphone Deterioration

I bought my Bose Hearphones in late August 2017, so they’re just shy of two years old, and have used them more-or-less daily since then. Although the innards still improve my hearing, the exterior is falling apart:

Bose Hearphones – cosmetic repairs

The conspicuous blue tips come from silicone tape holding the “soft touch” silicone shell together:

Bose Hearphones – detached band cover

The white line seems to be silicone glue holding the hard cover plate to the equally hard base. So far, it’s working, but the two-piece soft cover is peeling away from the very thin adhesive (?) holding it to the hard parts.

The silicone glue under the flexy cover on the control pod along the right earbud cable hasn’t fared as well:

Bose Hearphones – failed control cover

I blobbed ordinary RTV silicone under the cover, ignoring the caveats about acetic acid corrosion, because I don’t have any platinum-cure silicone on the shelf.

When the blue tape wears out / falls off, I’ll replace it with black silicone tape going further up the ring to hold the rest of the soft cover in place:

Bose Hearphones – cosmetic repairs – detail

The ear buds have soft silicone strain relief tubes around the cables. The friction holding them in place failed long ago and, because no adhesive will work with silicone, I wrapped enough double-sided tape around the cables to produce a sticky lump jamming them in place:

Bose Hearphones – ear piece strain relief

A bit of the muck sticks out on both ends and I expect to replace the tape every now and again:

Bose Hearphones – earpiece repairs – detail

I also expect to replace the non-replaceable lithium battery / cell in about a year, as they’re now barely adequate for a day’s use.

Fortunately, I can’t see any of this hackery while I’m wearing the things:

my face I don’t mind it,
Because I’m behind it —
‘Tis the folks in the front that I jar.
https://www.azquotes.com/quote/1243103

[Update: Bose apparently had a QC failure on the silicone covering and, much to my surprise, swapped me entirely new Hearphones. The new covering feels slightly different, the USB cable hatch is a distinct piece of plastic, and maybe it’ll survive until the battery gives out. Color me satisfied! ]

2019-06-19
Reversible Belt Buckle Re-staking

It’s a shorter belt with the same failure mode:

Reversible belt buckle – parts

I clamped the whole affair on a block to align all the parts:

Reversible belt buckle – alignment clamping

Drop the pin and spring in place, whack it with a punch, and it’s all good:

Reversible belt buckle – restaked

That was easy …

2019-05-19