The View Up Here

Random scribblings about kites, photography, machining, and anything else

Friggin’ Cable Releases

Posted by Tom Benedict on 24/03/2015

A year or so ago I bought a remote cable release for my camera. I wanted something that would do time lapse, long exposures, delayed exposures, you name it. Turns out there are scads of these things out there. They all seem to use the same basic electronics. The difference mostly lay in the packaging and form factor. So I picked one, used it, and got a lot of good use out of it.

In my post about batteries I mentioned that I managed to kill my cable release by letting the alkaline batteries I’d put in it go stale. And leaky. And corrosive. And… >deep breath< Whew! Let the past be the past.

Wireless Timer Release

Anyway, while shopping for a new one I saw that Yongnuo had a wireless version for not too much money. I picked one up off of Ebay, tested it, verified that it worked, and… promptly had it fail when I took it out in the field. It would focus on a half-press, but wouldn’t trip the shutter on a full-press. The weird thing is the display said “Release”, so I knew the switch was good. But it wouldn’t actually do anything.

The wireless release comes as two components: a handheld transmitter with a display, button pad, shutter button, etc., and a receiver that you stick on the camera. The receiver doubles as a cable release, complete with a shutter button of its own. When I tested it it worked perfectly! So I wasn’t entirely dead in the water. Just mostly.

The Yongnuo MC-36R also allows for a cable to be used instead of the wireless connection. Today I made a cable using some spare 1/8″ stereo headphone plugs and some spare wire I’d salvaged from a dead sensor at work. I built the cable, plugged it in, and… had the same exact behavior! Half-press would focus the camera, but the full-press did nothing!

Digital devices are usually pretty self-contained. Except for witnessing the battery-driven demise of electronics, there’s typically very little you can do to salvage something that has stopped working. But this was sounding a lot less like a logic fault in some chip and a lot more like a failed connection. So I opened the unit up.

The MC-36R has two circuit boards inside. One houses the LCD, buttons, and processor. The other houses the 2.4GHz transmitter, the channel-selecting DIP switch bank, and the 1/8″ stereo jack for the optional cable. I expected the connection between the two to be some sort of three-wire UART. Instead I found Vcc, Gnd, 1, and 2, and the #2 wire had popped out of the connector. ??! Each state of the switch had its own discrete wire! I shoved the wire back in and everything worked perfectly!

When I put the thing back together I saw what the underlying problem was. There’s almost no room inside the thing. The connector for the 2.4GHz board bumps up against the big honking half/full press switch for the shutter. So if one of the wires is even slightly out of place when the unit is assembled it’ll get pulled out of the connector. In my case the #2 wire was the one who lost. A little care during re-assembly and I avoided the problem.

I have to wonder how many of these things fail during QC testing. I wonder how many more are eventually returned when they quit working. In the event mine dies again I can replace the connector with a new one. It’s a 4-conductor micro-JST. I have a bag of them. Meanwhile I’m back up and running. And now I have a cable I can use, too.

– Tom

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