Electronic Test Equipment

 
Electronics is just one of those things where the tools are everything.  There is no way to “see or feel” the problem, so it all comes down to the toys.  Now, of course I do this for a living so I do invest a pinch more into the toys than you’re likely to do, but there are a few things you can do pretty cheaply.

First and foremost in my arsenal is the multi-meter (there are a lot of names for them out there).  Digital, or analog makes very little difference, it needs to read Volts, and Ohms (resistance).  Amps (current) is a bonus, and most cheap meters don’t read enough to be any use.  I’ve seen ok meters on eBay that sold for 0.99, and ones at stores for under 5 bucks.  Now of course these aren’t the best meters in the world, but they’ll do.

Don’t ignore the test leads.  Having a straight set of probes is the most common, but you’ll find a small set of clips pretty darn handy form time to time.

Get the really small test clips (Radio Shack 3.99), alligator clips are pretty big and you don’t want to short anything out.

 

 
Next up is the headset.  Headset?  Many time you’ll find yourself looking for a digital signal, (is the signal making it to the Gecko?).  For down and dirty testing and troubleshooting a headset works great.  You’ll notice I have a headset extension cord with the clips and the actual headset separate.  This way I can plug in amplified speakers (cheap PC ones work great) if I want to.
 

This is my newest toy, a hand held digital oscilloscope.  It is actually pretty cool and it works great for stuff like this, and at about $200 delivered it didn’t break the bank.

Now for most of you an o’scope is out of the question, and I would like to say that I didn’t have one for the longest time, but it was becoming a necessity so I popped for one.  I don’t expect anyone to go get one just to wire up a mill, but they can do quite a bit if you know how to use them, so this toy will solve lots of little problems.

I was an electronic warfare technician in the Army for 6 years, I know how to use a scope.

Making the Headset
 

I can’t really show you how to make the headset because I already have mine, but I can explain them.

If you want to directly connect the headset or use the headset extension cord makes no difference, the procedure is the same.  As stated above, the extension cord does allow you to play it through amplifies computer speakers, which can be bought for less than $10.

First, cut the jack end off the cord and strip back the wires about an inch.  You will more than likely end up with 3 conductors, left, right, and common (the shielding).  Twist all the shielding together, and twist the left and right conductor together.  Solder a small length of flexible wire to the common and put a clip on the end.  Solder a 400’ish Ohm resistor onto the left and right conductor and a wire with a clip to the other side.  Put some heat shrink tubing over everything and you’re good to go.

Now, this isn’t the most precise piece of test equipment on the planet, but it does work.  For the most part the human ear can hear tones in the 30hz to 17Khz range so that covers pretty much everything involved in a wire job.

To use them, set a pulse rate to the gecko using the computer (G00 X999) and listen to the step line, you should hear a faint tone.  Play with them for awhile, they do come in handy once you get the hang of it.

  Don’t go clipping these to anything that might have more than 10 volts potential.  The last thing anyone wants it to melt a pair of headphones to your head.