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.
Mechanical widgetry
After converting another fluorescent shoplight into an LED fixture, I tested its capacitors:
The ESR02 reports one as a 4.8 µF capacitor, the other as a “defective part” with a 4 kΩ resistance. Having a cap fail by turning into a resistor is surprising; I’m more surprised it didn’t simply burn up.
They’re visually indistinguishable, of course.
After not quite seven years, the acrylic caulk holding our garden dragonfly’s eyeballs in place lost its grip. Some cleaning of marbles and scuffing of copper sockets later, two rings of JB Kwik should do the trick:
It’s a family tradition, is all I can say …
So says the label on a recent Amazon package:
It contains half a dozen foam floor mat sheets weighing a bit under a pound apiece.
I don’t begrudge anyone working in an Amazon warehouse a bit of humor …
With six new 18500 lithium cells in hand, I rebuilt the three weakest NP-FM50 packs.
The Sherline CNC mill setup for sawing around the midline:
Adjust the saw to cut along the seam, set X=0 at the surface, jog to about X+0.7 mm, jog the saw along the seam, then repeat for the other three sides. No real CNC involved, but it’s much easier than sawing or breaking through the seam by hand.
These two packs came with the camera:
The cells have only lot numbers, no manufacturer ID. Wikipedia sayeth Sony Fukushima started in 2000; perhaps these were early production units with no branding.
The center strap running the length of the pack didn’t seem long enough, because I mistakenly thought I’d straightened its end while unsoldering it. As it happens, the end was straight and secured to the PCB by structural solder:
Moral of the story: pay attention, dammit!
The other end of the center strap required a snippet of tin strip to reach the tabs:
Aligning the cells that way allowed me to just bend the other tabs over the PCB pads and solder them in place:
Then a strip of Kapton tape across the kerf holds the case together well enough to survive our gentle usage:
The battery packs require a brief stay in the charger to reset the PCB’s lockout circuitry, after which they work fine:
The two oldest batteries (OEM 2003 A and OEM 2003 B) have new identities to suit their new innards: 2019 E and 2019 F. The DOA eBay battery retains its 2019 D label after the rebuild, as there’s little room for confusion.
Admittedly, it’d be easier / cheaper / faster to buy third-party NP-FM50 packs directly from eBay or Amazon, but this way I know the cells aren’t complete crap and I get some Quality Shop Time™ out of the deal.
What’s not to like?
A bit of rummaging produced a desk lamp arm, minus whatever lamp it originally held, ready to hold the second photo lamp, after a bit of epoxy on one locking knob:
The flanged nut will seat on the wrecked part of the knob, with the epoxy holding it in place and somewhat reinforcing the perimeter. I’m not sure this will last forever, but it’ll be a start.
Printing a second cold shoe, though, worked perfectly, and everything fit:
I love it when a plan comes together!
Having won an eBay action for a known-dead Sony DSC-F717 at $0.99 (plus $15 shipping, the seller being no fool), I now have a possibly salvageable camera, a Genuine Sony AC supply, and two more NP-FM50 batteries for about the price of any one of the components.
One battery arrived stone-cold dead, suggesting the camera had been put away with the battery installed for a very long time and they died companionably. The camera still charges a (good) battery, even though it doesn’t turn on, and perusing the schematics suggests checking the power switch, because it’s always the switch contacts. That’s for another day, though.
For the record, the battery status:
The red and green traces come from the two batteries I’ve been cycling through the camera since, um, 2003, so they’re getting on in years and correspondingly low in capacity.
The fourth battery (2019 D, the date showing when it arrived, not its manufacturing date) went from “fully charged” to “dead” in about three seconds with a 500 mA load, producing the nearly invisible purple trace dropping straight down along the Y axis.
Sawing the dead battery case around its welded joint at a depth of 0.75 mm, then prying with a small chisel, exposed the contents without histrionics:
Now, there’s a name to conjure with. Turns out Sony sold off its Fukushima battery business a while back, so these must be collectibles. Who knew?
The lower cell is lifeless, the upper cell may still have some capacity. Three pairs of 18500 lithium cells are on their way, in the expectation of rebuilding the weakest packs.
After desoldering the battery tab on the right from the PCB, it occurred to me I needed pictures:
Yeah, that’s a nasty melted spot on the case, due to inept solder-wickage.
Unsoldering the three tabs closest to the case releases the cells + PCB from confinement:
I’m still bemused by battery packs with a microcontroller, even though all lithium packs require serious charge controllers. At least this is an Atmel 8-bitter, rather than 32-bit ARM hotness with, yo, WiFi.
The cells have shaped tabs which will require some gimmicking to reproduce:
Now, if only I could reboot the camera …
On the drive side, of course:
I’d noticed some brake drag on our last few rides, but forgot to check until I saw the rim wobble while extracting images from the rear camera.
It’s a lot easier to fix in the Basement Shop than on the road. After nigh onto a decade since replacing the last broken spoke, perhaps this is a harbinger of doom to come.
Memo to Self: spoke tension is now 20-ish on the drive side, 15-ish on the left.
The Smell of Molten Projects in the Morning 