Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Having figured out what to do, I started with the button, which is chromed plastic, nothing too fancy, and not at all hard to machine.
Laser Aligning to the Button Stem
A small post turned from an acrylic rod (the gray cylinder) supports the button in the Sherline 3-jaw chuck attached to the mill table; that was the only way to keep it reasonably level. Laser alignment got eyeballometrically close to the middle; it looks a bit off to the right, but the end result was OK.
Removing the Broken Stem
A 2 mm end-cutting bit chewed off the stem in short order; I set the jog speed to about 100 mm/min and just jogged down until the cutter was flush with the button. Spindle at 4000 rpm, for lack of anything smarter.
I decided to go with a 1-72 brass machine screw, which is slightly larger (1.75 mm) than the original 1.5 mm button stem. That means I must drill out the bezel hole, as well, but the 1.5 mm diameter of the next-smaller 0-80 screws in my assortment was a sloppy fit.
A touch of manual CNC for the drilling, #53 with the spindle at 3000 rpm, Z touched off at the button’s surface:
G81 Z-4 R3 F150
The spindle was slow enough and the feed fast enough to keep from melting the button without applying any coolant.
I tapped the hole 1-72 by simply screwing the tap in with my fingers…
Chuck-in-chuck For Head Shaping
The 3-jaw lathe chuck doesn’t grip a 1-72 screw (no surprise there), so I grabbed the screw in the Sherline’s smallest drill chuck and poked that in the lathe. This doesn’t make for great concentricity, but it was close enough. The right way, as my buddy Eks reminds me, is to slit a nested bunch of brass tubing and use them as collets, but … next time, fer shure.
Button With Reshaped Screw Head
Anyhow, here’s what the button & screw look like so far. The backside of the screw head looks like it needs some cleanup; there’s nothing like taking a picture to reveal that sort of thing.
The pencil lead is 0.5 mm and the grid in the background has 1 mm squares, just to give you an idea of the scale.
My brother-in-law Tee dropped his Sony DSC-H1 camera, which landed atop its shutter button on the pavement.
Bad news…
the shutter button broke off
the bezel popped out
the teeny little snap ring that held the shutter button stem in the bezel vanished, because…
the stem broke and the end vanished, too
Good news…
apart from some scuffs, the camera still works
he managed to find the shutter button
and the button bezel
and the spring!
Shutter Button – Spring – Bezel
A bit of browsing reveals that many, many Sony DSC-Hx (where x is an integer from 1 through 9, inclusive) owners have the same problem, minus the inconvenience & embarrassment of first dropping the camera. Turns out that the shutter button stem breaks at that notch in normal use.
It seems the stem snaps while you’re taking pix, whereupon the spring launches itself and the button cap into the nearest river / drain grate / weedy area, never to be seen again. Tee is exceedingly fortunate to have found all the major pieces!
Shutter Button Stem – End View.
Here’s the broken end of the stem, with the button cap out of focus in the background. The stem is 1.5 mm in diameter, so the snap ring was surrounding, what, 0.75 mm of plastic? In what alternate universe did this design decision make sense?
I think the snap ring contributed to the problem by eroding the stem in the notch; that little white stub isn’t half of the stem diameter; it may have stretched under impact, but surely not all that much.
Yes, you can buy a replacement button for about 30 bucks direct from Sony, but it seems the new stem is subject to the same failure after a short while. They’re standing by the original design, marginal though it may be.
Now, obviously, this stem failed from abuse, no argument there. Everybody else had their stem fail without provocation, though, so it really isn’t adequate to the task at hand.
Bezel Socket View
Anyhow, there’s also some damage at the bezel socket on the camera body, but nothing major. The dented silver areas on either side of the switch membrane are ESD shields, so that any static discharge from your finger will (most likely) dissipate on the external frame of the camera, rather than burrow into its guts via the switch.
The bezel twist-locks into the camera body, which means that you can remove the bezel if you can get a good grip on it. It turns clockwise to remove.
Shutter Switch Closeup
Peering closer at the membrane switch, it looks as though the button stem did some damage on its way out, although Tee admits to using various pointy objects to trigger the shutter while figuring out what to do with the camera.
More good news: the switch still works correctly, including the focus function with the button half-pressed, That means the switch membrane and contacts are in good shape.
Bezel – Top View
The bezel itself is pretty well graunched, with a nest of cracks underneath that damaged arc to the left of the pictures. I think it’s in good enough condition that I can remove the bent plastic, ooze some solvent adhesive into the damage, and compress it enough to make everything stick together.
Bezel – Side View
Obviously, this calls for some Quality Shop Time!
The overall plan is to remove the remaining stem from the button, drill-and-tap the button head for a miniature brass screw (1-72, I think), reshape the screw head into a membrane-friendly plunger (about 3 mm diameter and flat), then put it all back together with a nut in place of the snap ring.
I should be able to install the bezel (without the button), then insert some drill rod through the hole to figure out how far the screw must protrude to trigger the focus & shutter switches. Perhaps a pin vise will grip the drill rod and bottom out on the bezel’s central ring, so I can do a trial-and-error fitting?
Then I can adjust the screw to that overall length below the bezel with the button pressed, whack off anything that sticks out above the button, adjust the nut to limit the button’s outward travel, slobber Loctite over everything, and put it all together for the last time.
That’s the plan, anyway. As the Yiddish proverb has it, “If you wish to hear G*d laugh, tell him your plans.”
There I was, bandsawing a 24″-diameter circle from 3/8″ plywood when the saw stopped cutting… which is how the bandsaw tells me that the blade joint just came undone. That’s what I get for applying too much torque to the blade, I thought…
As you can see, the joint I described at great length there wasn’t nearly as good as I thought. It has a nice wetted spot in the middle, but the rest of the joint didn’t bond. Alas, the ends of the blade sections had just enough molten solder to look as though they were bonded.
I’ve done other joints with that resistance soldering unit which held up well, but I’ll cheerfully admit I don’t have years of deep experience with it. Given the effort involved in making a bandsaw blade joint (not to mention the fact that I only solder up a new blade when I really need one), this is the first destructive test I’ve seen. It’s not like I’m going to solder up a blade, then tear it apart just to see how it worked, as I did with the nickel strip on those AA cells there.
A change of technique seems in order. The carbon electrode produces enough heat directly under it (which isn’t surprising, that’s how resistance soldering works), so I must cover the full joint area with enough oomph to get a good bond everywhere. That seems to be 1.5 seconds per zap, more or less, repeated as needed.
I have some machinable graphite that I could cut to be one square bandsaw joint at the end, plus a stub from a searchlight electrode that might work with less overall effort. However, a larger electrode probably wouldn’t heat the joint enough to melt the solder everywhere at once.
For what it’s worth, I tried to re-solder the joint without doing full surface preparation by grinding down to bare steel. Didn’t work, natch, which should come as no surprise; wasted half an hour futzing around before I gave up and did it right.
Memo to Self: Use the carbon gouging rod electrode, hit the entire joint, and don’t move until each zap cools!
I have a pair of underseat packs on my Tour Easy that have sagged rather badly over the years. That might have something to do with the fact that my toolkit and other odds & ends weighs more than some bike frames; while I don’t need that stuff very often, it’s good to have around.
Tools & suchlike live in the left-side pack, the near one in the photo, and you can see the problem. The right-side pack holds HT batteries, my belt pack, and other relatively lightweight stuff; I’ll fix that one when I see whether this works. The panniers at the rear wheel are for groceries and other bulky items. The trailer, well, that’s how we do groceries…
Broken Pack Backplate
Anyway, the underseat packs have a black plastic (styrene?) backing that cracked under the stress of the stuff inside, allowing the top corners to cave in and the bottom to droop.
The hooks holding the pack to the underseat rack were riveted through the backing sheet and the hardware, but a couple of good shots with a punch broke them free.
Some rummaging in the Parts Heap turned up a big acrylic sheet (“100 times stronger than glass!”) that’s absolutely the wrong material for the job: it’s too brittle. However, I’d like to see whether a stiff backplate will solve the problem or if I’m going to have to get ambitious and build an internal pack frame.
Acrylic Plate and Aluminum Stiffener
It’s essentially impossible to get a picture of a project built largely from acrylic sheet, but here goes.
I traced the outline of the old backplate onto the new sheet’s protective paper, introduced it to Mr Belt Sander to get those nice round corners, then drilled the holes. It turns out to not be quite symmetric, so there’s a right way and a wrong way to insert it into the pack.
All the hardware is stainless steel. They used aluminum rivets, which is the only reason I could punch them out without too much difficulty, that I’m replacing with SS 10-32 machine screws & nuts.
The aluminum stiffener is a random chunk of ribbed extrusion from the Heap; the original was almost exactly twice as long as one backplate, so the two halves (one for the other pack) are precisely right. I milled out the center rib around the nuts to get enough clearance for a nut driver.
Stiffener Hardware Detail
Herewith, a closeup of the hardware. There’s an acrylic sheet in there, honest, it’s under the aluminum extrusion and fender washer. Really!
I put an automobile license plate in the bottom of each underseat pack to act as a floor for all the crap inside; it’s an almost perfect fit and should give you an idea of the pack’s size. It also maintains the bottom’s rectangular shape and keeps heavy stuff from sagging; there’s a hole scuffed in the bottom from the intersection of a high curb and just such an oversight.
Tour Easy Underseat Pack Detail
Having washed the pack while it was apart (there’s a first time for everything), it looks a lot better than it did before. The yellow block in the front pocket is the kickstand plate mentioned there. It used to have a mesh pocket along the side, too, but that snagged on something and got pretty well ripped, so Mary trimmed it off when she sewed a patch over the aforementioned hole.
It’s still saggy, but the top corners of the plate are holding it up a lot better now. If they crack again, I might just have to go with some aluminum sheet.
These packs seem to be obsolete. The ERRC Lloonngg panniers (search for them) seem to be, well, too long for most purposes; they look as though they would interfere with ordinary rack packs. If I were doing it over, I’d look into hacking a pair of smallish duffel bags.
The oddly named Kensington “Expert Mouse” (it’s a trackball) sits to the left of my keyboard, where it serves as my main pointer controller; I’m right-handed, but have used a left-hand mouse / trackball for years.
Also, search for Kensington scroll to find other posts. There may be no good fix for scroll ring problems.]
Recently the scroll ring has become balky, stuttering upward & downward rather than actually scrolling. It’s an optical device, so I suspected it had ingested a wad of fuzz that blocked the beam path.
The top photo shows the infra-red emitter adjacent to the scroll ring’s slotted rim. The silver bar to the right of the emitter is the magnet that provides those soft detents. There’s no obvious fuzz.
Disassembly is straightforward.
Tip the ball out into your hand and put it where it can’t possibly roll off the desk.
Peel the four rubber feet off the bottom, remove four screws, and the top half of the body pops off.
Remove three screws from each of the two button cap assemblies and pry the button caps off the case bottom.
Remove two screws from the ball socket, pull it off, and clean any fuzz from the openings.
Surprisingly, I didn’t find much crud at all.
Scroll Ring Emitter and Detector
This photo shows the IR emitter and detector, peering at each other across the electrical isolation gap in the circuit board. Nothing obviously wrong here, either…
They both seem to be dual elements, which makes sense for a quadrature position encoder. Unfortunately, replacing them seems to be really difficult; they don’t look like stock items.
So I put it back together, plugged the USB cable in, restarted the X server (this being Xubuntu 8.10), and it pretty much works again.
Kensington replaced a previous Expert Mouse under warranty when one of the three minuscule red bearing balls that support the trackball went walkaround, but that gadget had been getting erratic, too.
I’m not sure what’s going on, but I have a bad feeling about this.
We have a bunch of Hobo Data Loggers recording various & sundry temperatures, humidities, and light levels around the house; as the saying goes, “If you observe something long enough, it turns into science.”
Normally the things run on single CR2032 lithium cells, which last for a good long time. However, Something Happened to the one that’s collecting groundwater temperatures at the water inlet pipe from the town supply: it started eating lithium cells like potato chips.
Hobo Battery Mod – Inside View
It was still producing good data, so I was loathe to toss it out. Instead, I figured all it needed was more battery, as a high current for a lithium cell doesn’t amount to much for an AA cell. A pair of alkaline AA cells produces just about exactly 3 V and the data logger can’t tell the difference.
So I opened the logger one last time, soldered the wires from a dual AA cell holder to the appropriate points on the circuit board, affixed the holder to the back with one of the case screws, and it’s been working fine ever since.
However, this seems like one more application where whatever plastic they thought would last doesn’t: the AA holders routinely split at the ends. Maybe the joint should be thicker, maybe it’s the wrong plastic for the job, but without the cable tie acting as a belly band one end of the holder splits off in a year or so. Bah!
Update: Maybe I got a batch of bad CR2032 cells, as the logger’s current seems to be just about right. Read the comments and then check the followup there.
Having gotten my buddy Eks back on the air with new EPROMs for his Tek 492 spectrum analyzer, here are the Tek 492 ROM Images (← that’s the link to the file!) you’ll need to fix yours.
[Update: the comments for that post have pointers to other images and a clever hack to use a standard EPROM. If you’re not a stickler for perfection, that’s the way to go.]
They’re taken from a “known good” Tek 492, so they should work fine: the firmware verifies the checksum in each chip as part of the startup tests; if it’s happy, we’re happy.
Because WordPress doesn’t allow ZIP files, I tucked the HEX files into an OpenDocument file that also contains the pinouts and some interposer wiring hints & tips.
If you’re using the OpenOffice.org word processor, you’re good to go. Open the document and get all the instructions you need to extract the files and put them to good use.
If you’re not using OOo, then choose one of:
Install OpenOffice.org (it’s free software, so kwitcher bitchin’)
Futz with whatever Microsoft claims will import ODT files (if it doesn’t work, don’t blame me)
Just extract the HEX files and do whatever you want (if you know what you want)
The trick, explained in the document itself, is that ODT files are just ZIP files with a different file extension, so any unzip program will unpack them. You won’t see the HEX files in the document, you must apply unzip to the ODT file itself.
After unzipping, you’ll find three HEX files in the directory that originally held the ODT file, along with the collection of files that make up the OpenDocument document.
Oh, if you haven’t already figured it out, the DIP switch on your board is also bad. Saw the damn thing apart with a Dremel tool, pry off the debris, unsolder the pins, and install a new one. Just Do It.
The Smell of Molten Projects in the Morning 