December 19, 2010

X-TRONIC 4000 Digital Hot Air Rework & Soldering Station

A little while ago I purchased an X-TRONIC 4000 off ebay to upgrade from my simple craft soldering iron.  Now that I have use it a few times I can properly review it.  First off, after doing my initial research there are far better soldering stations you can purchase, however they will be far more expensive. I was not willing to pay $250+, so I was limited to the this and the Aoyue 906 which did not include as much and was a little more expensive. So with that in mind, for a hobbyist who is looking for something better than your cheap plug in iron, the X-TRONIC 4000 is not a bad choice.  It also includes a very good warranty, and while still being manufactured in China at least it is held up to some level of ISO standards and is sold by a US based company. I was able to grab one for a little over a hundred dollars, so it is not so cheap that you would expect it will break in a few uses.  Plus the included backup heating elements prolong that even further.

The hot air gun works as expected, and was pleasantly quiet.  At worst I was expecting a fish tank pump.  At high air flow, which was way too much for circuit work, you could hear the light hum.  Yet at a normal air flow settings it was rather quiet, at the lowest it was whisper quiet.  I had no problem removing a surface mount chip off an old test board with some careful blowing and medium heat.  I expect any future part removal will now be done with hot air, as it make it very simple, or possible in the case of surface mounted chips which cannot be easily removed with an iron.  I also used it to heat some epoxy for removal and that worked as well.  With the three different air tips that are included, you will be set for basic use, though it does not beat a specialty nozzle for even heating.

The hot air gun is nice, but the main feature is the iron.  After using a craft iron for even delicate work getting a serious one is amazing to use. The soldering iron heats up in about 30 seconds, which is so much faster than the three to five minutes my craft iron would take. Also using the lcd read out and the control dial, the temp is more or less kept constant.  It is important to note that the temp displayed vs what is always applied still depended on the surface area in use . The ten included tips range from tiny to very thick.  For small leads, the small tips worked well, however for a lot of normal use you will need to use a thicker tip which keeps the temp far more even.  I understand this is not so much a flaw, as it is something normal with any iron of this level and power draw.  The included stand is nothing to brag about but it does keep the iron handy and away from burnable objects.  The cleaning sponge is thin and pointless, I will be replacing it with a brass sponge eventually, until then I will stick with a damp paper towel.  In short, this will be the start of many "why did I not do this earlier" life moments.

Overall if you are looking at getting a hot air gun and nice soldering iron this should work for you.  If you do not need the hot air then there are more actuate irons you can get for the same price.

December 14, 2010

Converting an PIR outdoor light circuit for 12v

Being lazy I did not want to turn on and off my circuit tree on my desk at work, so I was just leaving it off.  However, with the Christmas season upon us, people started to bug me about not leaving it on, so I decided to get creative and convert a PIR circuit from an old outdoor motion activated spotlight to run on a safer 12v and control the tree on my desk.

First off, after eagerly prying the circuit from the lamp I quickly realizes that it did not use a transformer like I was expecting.  Most newer lights I looked at did.  So I went out looking for a datasheet on the PIR controller ic, but the one used here is either too old, or is just unlisted. This was not going to be as easy as I was expecting it to be.

This was trouble some as every PIR ic has different pinouts, and some use a first/second amp other do not.  So I went back to the basics and traced out the circuit with my multimeter and carefully sketched out the paths so I could better see what was going on.  The first thing that stood out was the four large diodes which are clearly a rectifier, to convert ac to dc.  After this, it passes through the biggest resister (blue tube) I have ever seen, which drops the voltage down to around 13v for the relay which is switched by a transistor.  From there it is dropped further to 8v and smoothed out by a capacitor for the rest of the circuit. Which is odd as an ic usually takes 5v max, but as it was unlisted I only have the trace readings to go on, so I will assume it was built to handle a larger voltage.

After figuring out this much, it was not hard to see where I would need to apply 12v to have the circuit work exactly the same but at a far safer voltage.  So after removing a small resister to break the original +120v (black) path, I now had an isolated PIR circuit and a separate circuit switched by the relay.  Right now the relay will only deal with 9v, but this leaves it open to once again control higher voltages, for potential use at Halloween.

You can see the final result below.

I am quite happy that my digital/analog circuit skills have not gotten too rusty with all the programing I tend to focus on.