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.

Category: Machine Shop

Mechanical widgetry

Sony DSC-H5: Disassembly
The half-pressed shutter switch position on my Sony DSC-H5 recently stopped working, which seems to be one of two common failures. The other, a broken switch shaft, happened to Tee’s camera, as described there, and I figured I should preemptively fix that while I was inside my camera.

This being a common failure, several folks have described how to dismantle the camera; I followed that guide’s English version.

The DSC-H5 differs slightly from that description. After I got the thing apart, it became obvious that there’s no need to remove the LCD panel, the main control board, and most of the ribbon cables if you have a Philips #0 or #00 screwdriver with a very thin shaft. There’s no way to describe this operation, so take it apart his way, then you’ll see what I mean: the guts can come out as one big lump.

In any event, all the camera controls eventually emerge from the body:

DSC-H5 Control Assembly

Looking back into the camera body reveals the bottom of the shutter button, captured by a static discharge contact and the gray plastic frame of the Focus / Break button caps:

DSC-H5 Shutter Button – interior view

Removing the pushbutton frame and pushing the left button bezel latch with a small flat-blade screwdriver extracts the shutter button; it falls out of the inverted body. This is one of the few intact DSC-H[1-9] shutter buttons you’ll ever see:

DSC-H5 Shutter Button – bottom view

Those rectangular protrusions lock into the slots in the black plastic cap that appears almost silver in this front view that shows the dimple in the switch membrane:

DSC-H5 Shutter Button Switch – depressed surface

You must remove the cap to release the flex PCB with the shutter switches. Two heat-staked pins retain the cap; a scalpel neatly slices off the melted plastic:

DSC-H5 Shutter Switch – cover removed

Nota bene: the DSC-H1 button bezel I repaired earlier does not have features that lock into the cap over the switch assembly, which means you can remove and replace it without disassembling the camera. You cannot remove or install the DSC-H5 button without taking the camera apart. I suppose this counts as a continuous product improvement, but …

The shutter switch has two parts:
- The full-press switch that takes the picture (the white dot on the blue flex, shown above)
- The half-press switch that triggers the focus & exposure is in a black plastic tray (seen edge-on above the white dot)
The bottom of the half-press tray has a small nub that activates the full-press switch, so the force required to activate the half-press switch must be considerably less than the force that activates the full-press switch. This turns out to be a critical part of the repair…

A closeup of the half-press switch with the protective cover sheet (the “damn confetti” of the disassembly instruction) and the dimple that held the contacts together with the button released:

DSC-H5 Shutter Switch – dimpled protector

A closeup of the switch through a snippet of PET plastic shows the switch membrane itself is in fine shape:

DSC-H5 Shutter Switch – cover removed

However, the new plastic shield did not work out well, for reasons having to do with the new button plunger. That’s the next step: rebuild the plunger…
2012-10-22
Alarm Controls: The Right Way

Those aren’t alarm pushbuttons. These are alarm pushbuttons:

Submarine Albacore – alarm pushbuttons

They’re in the USS Albacore and obviously intended for use by someone in a hurry: the tactile shapes tell your fingers everything they need to know. If I understand the ship’s history, the Collision Alarm switch contacts closed only during tests, although they did have a close call with the sub towing the (unpowered) Albacore from the Philly boneyard to its final resting site.

According to the information we saw, the control board was refitted / replaced / redone to remove classified hardware, so the woodgrain Formica background may not be original. On the other hand, this was a sub intended for extensive experimentation, so maybe they used a cheap and easily machined material.

(Headfake to the Crocodile Dundee knife meme.)

2012-10-21
Boott Cotton Mills Museum: Along the Line

We stopped at Lowell MA to visit the New England Quilt Museum (photography prohibited) and the Boott Cotton Mills Museum (photography encouraged). The NPS, among others, managed to salvage the buildings and restore some of the machinery, to the extent that one room on one floor of one building has some running cotton mills:

Boott Cotton Mill Museum

A bit more detail:

Boott Cotton Mill Museum – line detail

The original mills used water power, as did much of New England’s industry, but moments after Watt worked the bugs out of that newfangled steam engine, water power was history. The museum uses a huge old electric motor, mounted on the ceiling, to drive the line shafts above the mills; the vibration shakes the entire building and they hand out ear plugs at the door, despite having only half a dozen mills operating at any time. The working environment, horrific though it was, attracted employees (largely young women) from across the region; it was a better deal than they had on the family farm.

Employees were, of course, prohibited from using cotton to plug their ears…

They sell the cloth in the museum shop and we’ll eventually have some kitchen towels.

2012-10-20
Screwdriver Rack

A while back I picked up one of Harbor Freight’s cheap screwdrivers sets; the largest two drivers far exceed my simple needs, but the smaller screwdrivers work surprisingly well. I couldn’t figure out where to store the things, as they’re used often enough to remain ready to hand, while being too bulky for any of the drawers. Emboldened by my success with those shoe latch springs, I decided to bend some coat hanger wire into simple clips that grab the screwdrivers around their waists:

Screwdriver clip – rear view

The first step forms a loop where the mounting screw will go; squeezing the wire around the pin with pliers made a reasonably good imitation of a screw hole:

Screwdriver clip – screw bend

The next two bends shape the wire to the arms; I eventually figured out that bending the wire ends to a mutual right angle worked out better than the acute angle you see here:

Screwdriver clip – second bend

Bending both wires at a right angle formed the arms:

Screwdriver clip – arm bend

Two more bends in each arm finished off the clip:

Screwdriver clip – entry bends

I chopped up a coat hanger with smaller diameter wire to make clips for the smallest screwdrivers with narrower handles.

Repeat that a dozen times, drill pilot holes into a ready-to-use bit of scrap lumber, screw the clips with 3/4 inch flat-head screws, add four more holes on the right for finishing nails to hold the red screwdrivers (which have suitable holes in their handles), screw the whole affair to the bottom of the floor joist, and it’s all good:

Screwdriver rack on floor joist

After running the first half dozen screws with great effort, I fetched the beeswax and the rest slid right into place.

The larger driver handles stick up inconveniently far behind the fluorescent lamp fixture that’s barely visible along the top, but (I’m pretty sure) I won’t use those nearly enough for that to be a problem.

I suppose I should dip the raw ends of the wires in goop to avoid harpooning myself; I think I’ll mostly handle the screwdrivers by their shafts, so maybe that won’t be a problem, either.

Memo to Self: Use the beeswax!

2012-10-17
Splinting an Umbrella Strut
One of the ribs in the six-passenger umbrella we keep in the van snagged on something and snapped its fitting on the spreader strut:

Umbrella strut – broken connector

This being wonderful engineering plastic that cannot be solvent-bonded, epoxy is the only adhesive that will work. However, those joints undergo tremendous stress in a deployed umbrella, so a bare epoxy joint won’t have enough strength for the job. What to do?

Wonder of wonders, when I got the umbrella into the Basement Laboratory Repair Wing, I discovered:
- The not-quite-round strut fitting stub slipped right into a short brass tube from the heap and
- Just enough of the fitting remained on the rib to anchor the tubing
A silicone tape wrap kept most of the epoxy inside while it cured:

Umbrella strut – epoxy curing

Clearing off a few blobs made it all good:

Umbrella strut – brass tubing splint

We don’t play golf, but such a big umbrella keeps most of the rain off two people; it’s a tchotchke from back when Mary worked at IBM (hence the color scheme). We call it our “six-passenger” umbrella because it looks about that big when we deploy it…
2012-10-16
Bicycle Mobile: New Windscreen Mic Ball

The bikes stand upright inside the van and the helmets ride on the floor with all their stalks sticking up. This usually works out well, but on our last trip my helmet rolled under my bike and rubbed the foam ball surrounding its mic against the chain, producing a result so awful that I had to install new foam.

For posterity, here’s the current state of the electret mic and its mount:

Electret mic on bike helmet boom

The foam comes from a sheet of Sonex acoustic foam baffle, snipped into a reasonable approximation of a ball, with a slit deep enough to surround the mic, and a cable tie holding it closed:

Foam mic ball on bike helmet boom

For what it’s worth, I’ve found that excessive wind noise correlates with too much mic gain. The mic rides about a finger’s width from the corner of my mouth, I talk at a normal volume, the amp supplies about 20 dB of gain, and we have no trouble with wind noise. The amp gain depends on the mic sensitivity, so your results will certainly differ; these mics came from the heap with no specs whatsoever.

I suppose wind noise also depends on the bike’s speed, but when I’m going that fast I don’t have enough brain or lungs left over to hold a conversation…

2012-10-12
Sink Soap Dispenser Pump: Nozzle Fitting

The absurdly heavy pump nozzle atop the kitchen sink soap dispenser seemed more wobbly than usual. Some investigation suggested the fitting atop the plastic pump has gotten smaller, which may be due to having the nozzle wobble around on it.

In any event, a wrap of Kapton tape snugged it up just fine:

Sink soap dispenser pump

We’ll see how long that lasts; this thing may be nearing the end of its useful life.

2012-10-11