Teardown: "HOTAIR GUN Desoldering Soldering REWORK SMD STATION 3 Nozzles RHOS Yihua 858D OZ"

Normally I wouldn't bother with a "teardown" post. They're popular, yeah, but I don't really see the point myself; it's like watching someone else eat ice-cream. But since I pointed out the potential & actual dangers of 'eBay special' hot air rework tools in my earlier post, I figured it'd be worth going through mine to uncover all the faults & explain them in a little more depth.

Opening it up, at first glance it doesn't look too bad:

Exploded view. (Note: comments and captions may not be literal…)

Crap that is useful: making it less crap

Following on from my previous post, sometimes there are fair reasons to buy crap. Which is fine, as long as you're aware that it's crap. Even then, though, it can be crap in surprising ways…

After hand-soldering tiny 3.2 x 2.5mm crystals in a couple of recent projects (& having to desolder & rework TSSOP-sized opamps to fix a pinout error … grrr, my own fault), I decided I needed a hot air rework tool. Since I'm not planning on using it a lot - I happen to like hand-soldering tiny components under a microscope* - I wasn't particularly interested in spending too much.

Enter the world of cheap and nasty hot air rework stations available on eBay. 57.50 Falling Pacific Pesos later, and I was waiting on AusPost to make me the proud new owner of a "HOTAIR GUN Desoldering Soldering REWORK SMD STATION 3 Nozzles RHOS Yihua 858D OZ".

(Alignment tool, random stuff, Fluke 19, and microwave analyser not included.
May cause death or injury in susceptible individuals or groups.)

Now, before anyone runs out and buys one on my say so (as if!), go read the thread on EEVblog titled "DEADLY WIRING FAULT ; Atten 858D+ Hot Air Rework Station". It's not just about the Atten branded ones; it's applicable to all of the cheap stations like Aoyue, Youyue, Saike, Xpower, WEP, Yihua, etc, etc. And not just minor issues - problems found include mains active wired to the metal barrel of the handpiece…

(Note: if you're looking for a teardown post, this isn't it - but I might do one later. Feel free to read on regardless!)

Crap that is crap

Cheap stuff is crap. Everybody knows this, including me, and we just deal with it. Here's one way that bit me last week…

The other day I needed a new heel for my shoe, so I decided to go to Morganville (which is what they called Shelbyville in those days) stereo 3.5mm cable for a couple of projects (a USB audio interface & a simple SDR; details in a later post), so I went down to the local sex-toy shop …

 Then ... and now ;)

… and bought a couple of cheap 3.5mm stereo plugs to upgrade my old home-made 3.5mm mono-to-stereo cable. Did the usual "be vewy, vewy quiet careful" dance when soldering them - gripped firmly (but not too tight!) in the soft jaws of the mini-vice (by the collar, not the shaft [as it were…]), plenty of flux, dialled in an appropriate iron temperature, used pliers to heatsink the terminals while tinning & soldering (so the plastic doesn't melt), etc, etc.

Result?

Why I Still Hate The Arduino IDE; or "How Come The NMU-7700 Software Isn't Ready Yet?"

I've been adding stuff to the NMU-7700 page over the last week or two - I wanted to quickly wrap it up for now so it's done, ready to build, & I could move onto other things. So far all the hardware stuff's there; what's missing is the firmware/software.

Which is where the post title comes in…

Sad news, but some good news

First, the sad news:

Ron, a.k.a. "Thinking Brain Dog", passed away a few months ago. Not only was he my friend, but he was the fingers - and at least half the brain - behind this blog.

And now, for my next trick...

With the heavy lifting of the memory unit out of the way, I'm thinking of other things. First cab off the rank is an improved IF buffer amp…

A few months ago I posted a quick write-up of a design I did many years ago, not too long after DRM first started appearing on the airwaves. It was a pretty straightforward JFET + 2 BJT design, nothing special - but it did the job. I've never been entirely happy with it though and, since that amp has graced a friend's set for years, I figured I'd build something better for mine ;)

An Updated Memory Module : Part 4 - It's Alive!

It's taken a while longer than I had planned, but it's finally done:

A fully-functioning, DIY, self contained, built from scratch memory unit for the FRG-7700!

I'm calling it the NMU-7700.