Fixing a Targano Digital Microscope

 Tip for 

It takes a microscope to fix a microscope. At work we have some Targano brand digital microscopes. They work well, and make a very good clear image for doing soldering work, but I have some gripes with their design. Not the loads of real working room below the imager, or the clear nice image it makes, but it SUCKS to repair this thing, and it's easy to break. A few weeks ago someone bumped into the scope at my friendly local soldering workbench trying to help with a video issue, and the microscope stopped working. Here's the ailing peeper of things:  

Unfortunately ours does not hover 2" above the tabletop, but what it does do is require you to plug a mini-HDMI cable into it's side like sticking a chest drain into a hospital patient with a collapsed lung. All that elegance in the marketing photo goofed by cable routing. I used our trusty old stereo fiber optic lit bench mounted look-sniffer to take a deep sniff down the mini-HDMI video hole and smelled a few pins that were bent by the right-angled and undersized cable getting a downward torquening.

 

Good old 'Ol-Reliable. You're always ready. With the problem understood, and with a heavy heart I ordered the cheapest 10 pack of mini HDMI ports on ebay that seemed like a likely match to the footprint, and once they came in I set to pulling the Targano apart. WHAT A PAIN!. They must not be making tons and tons of these, because they're built with loads of fiddly gotcha kinds of plugs annoyingly squished and squeezed into the extrusions of the outer shell. Also, there's strips of gaffer's tape hiding video signal cables in the upper part behind the stage light LEDs.

 

 Eventually after much fiddle-futzing I managed to extract the mainboard running the show, noting that screws to these threaded standoffs were held on not by their threaded holes, but by flush-tapered screws clinging for dear undersized life to a backing plate on the hinge assembly. Ehh, I've done hackier stuff, but with a "call us for a quote" price I'd expect a bit more serviceable and elegant design.... Either way, Next up was trying to improve my hot air work skills. masked off the area around the malign port with kapton tape, and promptly managed to hover somewhere between "smoldering black port plastic" and "The iron is set for 400c, why won't it melt?!" conditions. Eventually I got the old port removed, but it took 3 traces with it. Caramba.

 

With the old port out, a bit of fine solder wick braid made room for the new one. The image is better viewed in person in the microscope, but if you look carefully you can see the three missing traces to the fluxed up chips.

 

Look closely enough and you can see one of the patch wires i cut down to eventually fix the ripped pins. I tried using UV cure solder mask to glue down the traces and repair wires, but didn't manage to let them cure enough to be more than "glazed donut frosting" strong. Turns out that UV solder mask needs at least several minutes and the thinnest coat you can physically make occur to have a good chance of working.

 

 With MUCH ARDUOUS REASSEMBLY, the scope went back together, and you can pirate my index finger if you like. That done, I went ahead and made a shroud for the cable so it's not easily borked again. If Targano reads this, please redesign the board to use a full sized HDMI port at least?

Just a bit of aluminum sheet bent around and zip tied to the cable with a space, and one more to keep it tightly pulled around the upright of the thing, Maybe it breaks the elegance of the design, but what good is that when it can't take a light bumping into without nearly destroying itself?

 

 Pen Tip for scale, and spare mini-HDMI port for outrage. The hole in the case is sized big enough for it. Why not plonk a normal HDMI port on the board? Whatever. It's working again, and I only almost finished destroying it. Much clearer image on the Targano than the optical scope.

Spin the Wheel, no app, for real!

 A friend of mine has been running an occasional movie night at my local makerspace, choosing the film by way of a "Wheel of Flicks" app. While that gets the job done, nothing beats the real feel of spinning a wheel, and with nothing but junk laying around the shop I was sure we could cook something up.

 

 

 

 

 

 

 

 

 

 

 

 

First thing was the wheel, and a means to hold it. I was going to use a 40" chunk of dimensionally questionable 3/4 ply i had laying around, but after cutting it into a lovely circle on the table saw, a couple folks pointed out that we had a perfectly 70s table top chilling in the parts piles. It was just barely smaller, but more importantly, it was flat and smooth, and had nice T molding already running around it's perimeter. I put my plywood circle where the table top was to not upset the shop's feng shui.

We scribed the middle from a bunch of angles on the back until we found the center point and drilled it out. A stack of four 608 skateboard bearings in a 2x4 and a through-bolt sized for the inner races did well for an axle. a plastic puck and threaded nut insert make the amount of compression on the wheel adjustable. Thrust bearings would be nice, but meh. There's a little bit of drooping, but not enough to matter much, and I added a guide wheel for that later on the back anyway.

 While my buddy laid out the spans between the pie wedges, I chopped down an length of nice stainless rod recovered from an old large format printer. We needed 16 pins total, and by sheer luck I managed 16 pins and 1/2" of scrap in the end. NICE. They were hammered into friction-fit holes around the perimeter once we had the masking tape sorted, and that really started selling the look of the whole thing. Given the breakneck and freeform pace of designing it on the fly, and needing it painted and dry tomorrow, we opted to let the wood show between the painted wedges. Call it an homage to 1970s game shows I guess?

 To expedite the painting process, i made a couple of masking wedges from hardboard scraps, and painted half the wedges on the wheel.

 With the first 8 of them done, i went back inside to work on the frame and supports. The host of the movie night had a great idea to make the frame's base from a foldable sawhorse, and to make the whole thing break down for storage. Some bits of 2x4, carriage bolts, and lots of long drywall screws, plus some rattlecanning of the whole frame and it looks ready for TV. Maybe like, 1970s tv in 240i so you can't see all the overspray and runs in the paint.

 

 

 

 

 

 

With the frame mostly sorted, and the paint on the first 8 wedges arguably somewhat dry, i did the second batch of wedges, and cleaned up shop a bit. while it dried enough to bring inside.

 

 

 

 

 

 

 

 

 With both parts put together, and the masking tape pulled it started looking pretty snazzy, and you can't see the flaws in the paint while it's in motion, so clearly the answer to quality control issues is to keep it moving whenever possible.

 

 

 

 

 

 

 

 

The only thing left to do was give it a clackety dial. I was mulling over cutting out custom indicators, and using springs and more complex mechanisms to show it's choice, but in the end, went with a quick and dirty bit of hardboard  wedged into a block on the frame. Minimum Viable Product is sometimes good enough, and we can always improve it later.

 Next up would be makign some kind of mounts for the films more than just strips of painters tape with names on them, a marquee for the WHEEL OF FLICKS and improving the overall finish, but it's ready for movie night and we have one less app to worry about now.

The Red Light Therapy Light

Tonight on "why did this not work?" A red light thingamajig:

 
The issue: not maek light.Oughta should. The display comes on, but no light, red. IR, or otherwise.


So..... The AC adapter seems of good repute according to the sticker. FCC and proper CE listed. CUI Japan makes good power supplies according to easy research. The red accented sticker on the back of the unit seems confused though. You don't list the input voltage of your wall wart on the unit. You list the voltage the unit needs.... If you plonked 85-265v of any flavor into this thing it's let all the smoke out in dramatic fashion.

 
It's hard to read, but the electrolytic cap next to the input plug is 36v rated, not what you'd expect of a 12v rated device normally....


The 24v rated fan also points toward the 12vdc wall wart that came with this light being weird/wrong. It doesn't spin on it's on at 12v, but the most gentle spin makes it turn gently.

Traced down one stretch of the board. White solder mask on an aluminum substrate board is good design for a light, but annoying to reverse engineer. Blue sharpie shows it as 12 single LEDs in series, or 2.0VDC drop at 24v input. popping an 2032 cell across each LED confirmed they all worked fine. 3v may or may not be a little hot for non-blue/white LEDs, so don't cook em long.


Finished out that section, and it's a little odd. 10 LEDs, sharing the head and tail of a couple of the string of 12 LEDs on the top half. 2.4v is still fine, just an odd design. Either way, onward with the suspected 24v expected input.

Dug around the Bucket-o-AC-Adapters, and by God a 24v plug is just what the doctor ordered.

If you turn off the visible red LEDs the IR ones light with the typical "barely glowing to the eye/FIERCELY INTENSE to the camera" kinda blast.

Why did this device ship with a 12v adapter on a 24v device? The world may never know. But it blasts hella bright red blind spots to anyone interedsted.

Taming the wild LED bulb

A few years back BigClive did a great run of videos on the now ubiquitous Normal LED Bulb, how they're driven, how they're usually overdriven to make them die faster, and how to chill them out by replacing their current limiting resistors.
https://www.youtube.com/watch?v=5HTa2jVi_rc
I tried my hand at such a mod today, grabbing the first bulbs in my stash that looked about right.


Can you guess which I've already messed with? Anyway, the long and short of it is to clip or rip off the original surface mount current-setting resistors and plonk on a 220 ohm resistor to the same points, and it gives you a light that'll last for many many more years than it originally would, and divides the original output by 1/10 or so for most bulbs.


The unmodified bulb, original resistors by R4 and R3.

Modded with a 220 ohm resistor. The spring clip is common with the now empty right resistor pads.

 
The camera really mutes the difference between the two, but subjectively the one on left is about 1/4 or less bright than the one on right. The reflection on the ceiling tile/metal is a decent indication of the difference.


Now the kitchen can be minimally lit anytime.