Shitty Amateur Electronics - Part 1: An Early Casualty

One of my issues with hobbies, as I’ve mentioned, is that I’m quite flakey. Essentially this manifests itself by me getting into something for a few months and either reaching a level beyond which I cannot understand or progress, or I just burn out and get bored quickly. I have two paintball helmets in our storage room.

Oh, by the way, I do electronics now.

My mother heeded my dropped hints for a soldering iron set for my birthday and I then bought a starter electronics kit to make some easy circuits that I could interface with using a Raspberry Pi. I’d also wanted to add a hard reset switch to my Pi so I didn’t have to unplug and replug in the USB power whenever I halted the system. This seemed an ideal time to start playing with components and get some soldering practice in. What I didn’t know about was the can of worms I’d open in the process...

On the Raspberry Pi there are two contacts on the board which, when shorted out, will cut power to the device until released, at which point the system will boot from cold again. I’d need to solder a two-pin male “header” to these contacts so that I could plug in a prepared cable and button assembly. Should I test my soldering first? Practice on something I don’t need? No, of course not. Let’s dive right in.

I had flux-free solder for this at first. It came with the kit. Probably not good since it doesn’t flow as well around the required area (so *that’s* what flux does!). I eagerly grabbed my RPi 3 LibreELEC system and tore the board out of its case. I managed to put the header through the holes and somehow hold it in place with one hand while also holding a soldering iron and solder reel with another. And maybe an implement or two to steady things.

No, I have no vice. One for the shopping list.

Heating up the board and contact point before applying solder seemed to help a bit, but before long my usual thing happened - too much solder. And I didn’t have any solder wick to suck it up. And solder suckers are a bit shit, I’ve since discovered. But I managed to clean it up a tiny bit and after wiring up a switch on the other end and inspecting it all closely I plugged it all in and... nothing happened.

I couldn’t figure it out for thirty minutes before realising that I’d wired the switch across the two sides that are joined together and the split is in the middle, so wiring across those joined sides meant it was always closed. I used 1 and 2 instead of 1 and 3. Lesson learnt: check the pinout - I’ve played Shenzhen I/O and I can’t believe that I forgot that.

By the way, all this time - about thirty minutes - I’d forgotten to disconnect the power from the Pi. so it was feeding it all to ground. Is that bad?

Anyway, I rewired the switch and then... it worked! Then I put the board on the table and it reset. Bugger. Must have shorted the pins. I tried again, melting the solder and resetting and separating them, cleaning them up as best as I could. It worked! For a longer time this time. And then thirty minutes later it died. Only the red power LED came on - no other activity.

For good this time.

OK, let’s remove the header, clean up the solder as best I can and see if that’s the issue. The pictures below show the results of this effort from both sides.

Preeeetty good? There’s no joins as far as I can see. Maybe I damaged that track that goes to and from that square hole. No idea. But even after doing this it still didn’t boot. My RPi3 was dead. I still have no idea what happened. Did I short something out? Or was the half-hour of feeding the power through the closed switch to ground the problem? Christ knows. But it’s dead.

So, a dilemma: do I try again on the zero? Find out in the next episode of Shitty Amateur Electronics.