Electronics 2 – Michel 0

Tonight I was defeated again. This week yet another piece of equipment broke here at home and I decided that maybe I could fix it myself and not have to spend the money buying a new one. Well… I’ve ordered a new one!

Let’s start from the first battle: my espresso machine. It was not a great machine, but it had some sentimental value, as it was one of the first presents that I’ve received from my now wife. So one day it decided to not turn on anymore. So I brought it downstairs to my shop and decided to take it apart.

Well, it first started by needing triangle head screwdriver. Asked around if anybody had one, but ended up having to buy one. And then the process started (I know, I need to learn to take pictures of those things)… To soon find out that I really couldn’t do much without breaking some of the parts of the machine. It wasn’t meant to be serviced.

Finally, after taking it apart in a non-recoverable way, I looked at the internal components and couldn’t find anything wrong with it. Wires seemed connected (which was my theory why it wasn’t even turning on) and all the components (mostly all passive components with interesting embedded thermo-diodes for temperature control) looked like they were in good condition. So I gave up and gave myself a new espresso machine for my birthday.

Then onto my next fight: my headphones. After almost 5 years of daily use, one of the cables decided to rupture on the base of the thicker part (where there is a clip to hang on your clothes). I though: it’s just a small cable, I can solder it back! Well, it was on the base of a plastic piece, so I had to cut it open to get enough wire to solder things together. Let’s say that after hacking it around, I was not able to get enough wire to make a stable connection.

So then I had this brilliant idea: why don’t I cut the wire before and after this clip holder and then have much more wire to sort it out. Well… To my (not completely unexpected) surprise: there were 3 cables going into the thick part (and a wire mesh around it, which I assumed it was just grounding), and 4 cables going out, two to each headphone. Red, white and black, going to two black pairs, but one with white dots.

Looking around, my conclusion was that the white cable was ground, and the red and black were left and right (or vice-versa). So far so good. So I just needed to confirm it. I connected the white and black on one earplug and… Nothing! I changed to white and red and… Nothing! Then I changed to red and black and I could hear the sound! How could it be stereo if only one combination generated sound? I even connected it to my osciloscope and saw the same thing!

Well, I then decided to open up the thick part to see how the connections worked. After hacking around more I learned two of my problems:

  1. Actually the white wire was disconnected. The ground was only connected to the wire mesh around the cable.
  2. Inside the thick part actually there was a small electronic circuit, basically two diodes, one for each red and black that I think were basically there for protecting the earplug circuit from spikes.

As I didn’t want to risk the diodes actually protecting my iPhone and not the earplugs, I decided to admit defeat and just buy a new (and less expensive) pair of headphones. Let’s see how much they last me. The only problem now is that I have to go to the gym without headphones until the new ones arrive…

And that’s it. I probably should return my EE Ph.D… All my professors right now are ashamed of my performance. I’m sorry. I should get back to developing software, which is something that works more often.

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