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: Improvements

Making the world a better place, one piece at a time

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
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
Vise Handle Bumpers

Bench vises (not vices) have heavy steel handles that clank when the ball end slams into the hub. You can fix that by slipping suitable rubber washers over the balls on each end:

Vise handle bumper

After which the handle gives off a pleasant thump and won’t nip a careless finger.

This is an old trick and certainly not original with me; the occasion being that I just replaced the old and much-abused washers which were letting the clank through again. IIRC, a retail package consisting of both red rubber garden hose washers and black rubber O-rings followed me home from a tag sale, so I used both.

2012-10-04
Tour Easy + BOB YAK Trailer = Cargo Hauling

Friends of ours planted a few dozen Liriope spicata as a border around their nicely trimmed flower garden. This did not work out well, as the stuff spreads like a weed and duplicated beyond their wildest imagination. However, this part of the description caught our attention:

No serious diseases or pests occur for creeping lilyturf. […] Lilyturf is reported to have little wildlife value.

Translation: nothing kills the stuff and deer don’t eat it. Sounds like exactly what we need for the section of the front yard that slopes down to the road, where mowing poses a threat to life & limb.

We said we’d take it, they dug it out and bagged it, I hitched up the bike trailer, and we paid them a visit:

YAK Bike Trailer – 55 lb of grass

They’re a few miles off the south end of the Dutchess Rail Trail, which is (by definition) pretty much dead flat and made the trip a lot easier: that load of grass added up to 55 pounds! They dropped off a few bags on their next trip past our house, which tells you how much they wanted to get rid of it.

I wielded the post-hole digger to prepare about 100 sites, shook the dirt off the existing grass roots to backfill the holes, we divided the new clumps by chopping them with a shovel, and a day later we had everything installed and watered down:

Liriope spicata planting

I’m liking it already…

2012-09-29
Garden Hose Ball Valve Handle Replacement

The handle cracked and fell off this ball valve while I collected the hoses and suchlike from the Vassar Farms plot:

Ball valve with broken handle

Surprisingly, it’s not plastic, but (most likely) some cheap & grainy pot metal that wasn’t designed for durability. Rather than throw out that nice brass and stainless steel valve body, I figured a new handle was in order.

To the Basement Laboratory Machine Shop Wing!

The ball rotates freely inside the valve with the handle missing, so I found an aluminum rod (which, IIRC, was the original kickstand from my Linear Mach III ‘bent) that exactly fit the ball opening’s ID:

Ball valve – removing nut

What with it being a dark and stormy night outside (and having shut down all the computers in anticipation of a monster thunderstorm), I decided to get medieval with some hand tools. The first step involved finding an aluminum plate of about the right size and thickness, with markings left over from whatever I’d been building when it last saw the ceiling lights:

Ball valve handle – initial layout

After carefully drilling & filing the shaft hole, it looked like it’d work fine. Then I realized that, for whatever reason, the original design aligned the handle parallel to the hose when the valve was closed, which made very little sense when analyzed according to the Principle of Least Surprise.

So I drilled-and-filed another hole on the other end at right angles to the first one:

Ball valve handle – proper alignment

The original handle had two bumps molded on the bottom that acted as stops at each end of its 90° rotation. I figured a pair of 10-32 screws would suffice, not to mention they’d provide a bit of adjustment in case I blundered the hole positions. I planned to chop these stubs to whatever set the proper length below the plate:

Ball valve handle – trial fit

It turned out that the proper length was just about exactly that of a 1/4 inch 10-32 set screw flush with the top of the plate, so that’s what I used instead. They’re located one radius out from the outline of the valve body; trace the body shape on the handle in each orientation, eyeball one setscrew radius out from those intersections, and drill the holes.

Lay out a nice handle shape by eye, rough it on the bandsaw, introduce it to Mr Belt Sander for final shaping, touch up the concave corners with a rat-tail file, scuff the flat surfaces clean with a Dremel stainless steel wire brush to produce a used-car finish (nice polish over deep scratches), and it’s all good:

Ball valve handle – top view

The knob on the end is actually a foot intended for the bottom of a widget case:

Ball valve handle – bottom view

It won’t get leak-tested until next year, but what could possibly go wrong?

One thing, perhaps: that screw likely lies too close to the hose, particularly one sporting a replacement connector. I may be forced to bend the narrow part of the handle up a bit…

2012-09-28
Wouxun KG-UV3D: Improved Knob Index

After Raj thoroughly shamed me for slobbering white glop on the KG-UV3D’s volume / power knob, I hereby repent…

Clamp a cutoff chunk of 3/16 =0.1875 inch diameter brass tubing in the lathe and file down one side to put the flat 0.150 inch from the far side, so that the knob is a tight slip fit. If you happen to have some solid rod, that would work just as well. In this case, the file pushed the paper-thin brass remnant into the tubing and I didn’t bother to clean it out:

KG-UV3D knob with fixture

Clean the white glop off the knob, jam the knob on the fixture, clamp the fixture in the Sherline’s vise, use laser targeting to center the spindle on the notch adjacent to the minuscule pip on the knob:

Laser aligning to knob feature

Drill a 2 mm recess that en passant obliterates the pip:

Drilling index recess

Fill it with some light gray paint that just happens to be on the shelf:

Knob with filled index mark

And, by gosh, it really does dress up the radio! [grin]

Wouxun KG-UV3D with improved knob

While I had the Sherline set up, I did the knob for the other radio, too.

Thanks, Raj… I needed that!

2012-09-12
Vanagon iPod Interface: Minimal Edition

My buddy Duggles, from far-off NH, restored his ’83 Vanagon to its original hippie-chick-magnet state. Late in the process, he realized that the once-fancy CD+radio widget in the dashboard lacked a line input for his iPod / iPad / iDingus. Knowing my foibles, he asked for advice.

Fortunately, he’d already discovered the service manual, without which life is always much more difficult. Search for PIONEER DEH2850MP SERVICE MANUAL and pick the site you prefer.

My first email went a little something like this, with a few updates:

BEH2850MP Audio Mux

The trouble with jamming a new line input into the existing circuitry is that you must match the DC levels as well as the audio amplitude. The schematic on page 19 shows the selector IC has capacitor-coupled inputs and outputs to strip off the DC level.

It would be very easy if the multiplexer (IC151, top of page 19, detail shown) had separate control inputs that we could override, but it uses a serial control stream from the CPU. No practical way to mess with that, alas.

As nearly as I can tell, the best way to do this would be to hack a DPDT switch between the FM/AM tuner and the amp, upstream of the mux. You pick the Radio input, flip the DPDT switch, and the iDingus plays through the Radio inputs.

However, an easier way is to simply inject the iDingus audio in parallel with the tuner audio, but set the tuner to an FM frequency without a radio station. The radio output should mute, leaving the field clear for the iDingus audio. This might not work, but it’ll be dead simple to try. If it’s acceptable, then you’re done.

The obvious problem is that we don’t know if the iDingus line level matches the tuner’s line level. The mux is upstream of the volume settings, so there’s hope that this will all Just Work. If it’s way too loud, that’s fixable. If it’s too soft, that’s a problem.

So, to begin…

DEH2850MP PCB Radio Jumpers

The diagram on page 36/37 shows the A side of the PCB, with all the connectors & suchlike. The FM/AM Tuner Unit is over along the right side, with the audio output on pins 23/24 near the bottom and ground on pin 22. The traces proceed upward along the edge of the PCB, cross the connector near its middle, the audio passes through caps C151/152 on the B side, go through two jumpers on the A side across a mess of traces, and then dive to the B side and wriggle into the IC151 mux.

Quite conveniently, the ground trace follows along with them and is the lower of the three traces just to the right of the mux.

If I interpret the part number for C151 correctly (page 45, top right):

C 151 ... CKSRYB224K10

it’s a 220 nF cap. Anything around that value should work. This one from Radio Shack is grossly overpriced; anything with the same or larger value is OK (voltage rating doesn’t matter): NTE MLR224K100 – 0.22MF 100V Mylar Capacitor

Solder one lead of each cap to the top two jumpers, solder suitable wires to the other cap leads, solder the ground / shield wire to the bottom jumper, solder a suitable jack to the cable, plug iDingus into jack, fire that mother up, and see what happens.

The right channel is on pin 24, which goes to the top jumper of the three. Don’t bother trying to figure out which pin of the iDingus corresponds to that channel; just solder the damn wires and fix it later if it’s wrong enough to be objectionable.

I have no idea where or if you can drill hole(s) to snake the cable(s) through the housing. If the Vanagon doesn’t have a rear power amp, you could probably cut the traces under those RCA jacks (CN352, top right on page 37, above the FM/AM tuner) and repurpose them.

Give it a go…

We both attended Lehigh U, but Duggles realized early on that he lacked the personality flaws common to engineers and bailed out before damaging himself too badly. So his reply didn’t surprise me in the least…

I read your instructions carefully, examined the kindly supplied circuit diagram, and pored over the circuit boards with a magnifier. Then I blew you off (!!), threw caution to the winds, hacked off an old headphone cord, snaked the wires in, and soldered right to the very convenient L/R outputs on the RF board. Fired it up ,,, shitz, tons of background hiss, no quieting on the FM signal! A skein of obscenities was loosed in the mountain air until I thought to turn the iThang on … boom, full quieting, no hiss, and a quite substantial sound. No level issues at all, quite clean and detailed, and I didn’t even use the capacitors! (What was their purpose btw?)

After observing that a prophet is not without honor, save in his own land, I couldn’t resist going full-frontal didactic again:

The mux has a DC bias on its signal lines, with caps on both the input and output to isolate it from the surrounding circuitry. Back in the day, analog switches were fussy about their DC bias, so you had to go overboard to make them work at all.

I don’t know if the iDingus also has DC blocking caps on its output and figured that injecting raw DC from the mux into its guts could be a Bad Thing. But, eh, those engineers at Apple (‘s contractor) are smart folks and (probably) anticipated this sort of (mis)behavior.

The hiss you get with the iDingus turned off probably comes from dragging the mux bias to ground. I don’t know that’s a Truly Bad Thing, but adding those caps should eliminate any future problems.

You could even play DJ by combining radio & iDingus audio!

Rock on…

Seeing as how Duggles actually was a DJ for quite some years, I wouldn’t be surprised in the least to hear he does exactly that. We’ll be visiting him later this Autumn and I’ll inspect his work.

I love it when a plan comes together…

2012-09-10