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Thoughts on software architecture and development, and methods and techniques for improving the quality thereof.

David B. Robins (home)


Code Visions: Improving software quality
Flash emergency and aftermath

By David B. Robins tags: Tools, Embedded Sunday, September 3, 2017 17:25 EST (link)

Last Christmas we drove up to my parents' place in Canada for the holidays—we alternate years (so the first year with Wee Tiny goes to the Hedricks). Of course, I brought my camera (Nikon D300; I've been Nikon since film and my F90X, and have the lenses to show for it), but it had been a while since I'd used the external flash (an SB-800) and I found the batteries had leaked and corroded the contacts to the point it no longer functioned—horrors!

I did not know if it was simply a break in the circuit, and I'm a long way from most of my tools, but I think I had a multimeter with me, so I could buy a set of batteries I knew worked (reduce one variable), but… nothing. I looked around, and sliced up a Coke can with a set of tin snips to use as a conductor between the battery +/- ends instead of the corroded connectors on the battery door. Still didn't work. Looked around online, discovered that aluminum had a tendency to oxidize and not conduct, roughed it up a little, and finally got power. Realize I'm not looking for a long-term fix yet, just to find if anything will fix it or I'm looking at replacing an expensive flash unit. Turns out the Coke-can shim worked for the rest of the holiday, and I was careful to remove the batteries before we headed back to the US.

When we got home, I thought about a more long-term fix, since every time I wanted to use the flash I had to finagle the aluminum shims in place (not wanting to leave batteries in again). This would matter more when I upgraded to the D850, which had no pop-up flash; and the pop-up is terrible for indoor lighting anyway.

So I had a couple ideas: try to find a replacement battery door—which I did, on Amazon, and although the source looked a little sketchy it seemed like the right component, but not cheap; or maybe solder a short wire to the batteries' +/- together pairwise (it takes 4 x AA) so they can be inserted quickly. I read a little online about soldering to batteries (and learned about the existence of batteries with pre-manufactured terminals), mainly to ensure it was safe. I tried with a dead battery; worked out poorly, the solder didn't want to flow to the battery. I didn't have any flux handy, but filing it rough allowed me to deposit some solder and then connect a tinned wire. So that would have been fine.

But an easier solution presented itself: clean out the corrosion (first with the file, then with Q-tips dipped in vinegar), and if that removed too much material, I could deposit some solder to use as a cap. The solder wasn't necessary, and the simple act of cleaning it out well restored the flash to use.

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