Andonstar Microscope

Project 30 : Look inside the Andonstar 2MP Microscope

The Andonstar microscope is a very handy tool, and readers of these pages will know that we use it often here at NoYoo.

Exhibit 1 Andonstar Microscope

Unfortunately,  our Andonstar pulled up faulty … unable to connect to the USB port, it looks as though it has lost it's device ID, both manufacturer and product ID. And despite much effort, changing PC's, drivers, USB ports etc etc.. we have been unable to find any  joy..!

Well there is value even in death, and what an opportunity to pull it to bits, and have a squiz inside ..

Almost the first thing you notice about this Andonstar Microscope is the build quality, all the way through there is a lot of attention to detail even given the low $60-80 price tag.. Now for the tear down...(click any photo to get a full size view)

Exhibit 2 -Screw in lens

First step is to remove the screw in lens, this is not tight, easily removed with your fingers... though it is small …

Exhibit 3 – Lens removed

With the lens removed, you can get a better look at the LED ring, I found this was glued in place, even though it is good pressure fit. A small screw driver will let you lever the LED ring out, but do be careful there are two fine wires attached to the LED ring (See Exhibit 4 below)

Exhibit 4 – LED ring removed

The LED ring is still attached, by two wires that run the full length of the outer tube  and down the sides of the camera CCD as we shall see later

Exhibit 5 – Cable Ferrule

Now to start at the other end, the microscope barrel is held together by an aluminum ferrule. It is threaded on, but has no flat surfaces, so careful application of some large pliers (or multigrips), will loosen it. I noticed some form of grease or adhesive also here, but it did not look like loctite. Anyway this is also  is reasonably straightforward.

Exhibit 6 – Everything now loose

Undoing the ferrule you will be able to slide the knurled knob up the cable, which will reveal too slots in the body of the microscope. Embedded in those two slots are two tiny brass pins which slide the whole mechanism up and down based on the operation of the knurled knob.  Remove the brass pins with a pair of tweezers. Careful not to lose these pins, they are tiny

Exhibit 7 – Brass Slider Pins

Note here, these pins are ~2mm and interestingly  they looks to have a machined rebate at on end .

Exhibit 9 – Circuit Board Exposed

Now carefully push the whole assembly forward from the cable end, and the entire circuit board will be released. You can see a double sided board, two wires run the full length for operate the LED ring, and the cable is glued to the board with 'hot snot'.

Exhibit 10 removing the 'hot snot'

I clamped the cable, then using a knife blade to prise away the hot glue and reveal the cable terminals on both sides of the board. This allowed me to do some continuity checking on the cable.

Exhibit 11 – LED ring exposed

Starting at the far end, the LED ring comprises 8 LEDs , which are current controlled by a chip on the PCB, and directed by the potentiometer wheel in the middle of the cable. I will include a circuit of this part at the end of this article.

Exhibit 12 – Bottom side of the board connections

Scraping away the hot glue revealed three wires on the bottom side. One lead for the SNAP function (to take still photos) using the integrated switch on the cable, and one lead for control of the LED brightness, and one ground lead (GND)

Exhibit 13 Top Side Board Connections

On the topside of the board are three connections also , two data leads DM, DP to send the digital video  signals up the line to the PC, and +5V to power the microscope from the PC's USB connector.
This is an interesting approach, given there are 6 wires, and that a USB 2 cable only has provision for 4 wires. (check out the circuit notes below)

Exhibit 14 – Camera CCD DIE exposed

At the other end of the board, on a daughter PCB which is at right angle to the main board is the 2 Mega Pixel camera DIE. Note also the are two flat sides to this board, these flats provide the space for the LED ring wires to pass down the length of the microscope tube. This is important during reassembly.

Exhibit 15 – SONiX Chip Exposed

The largest chip on the main board, is a SONiX SN9C236BJ6. This is a somewhat elusive chip, as I was unable to find a data sheet anywhere that matched.

I did find several with similar numbering (using the prefix SN9C2...), which are full blown 1.3MP camera DSP, Driver and USB all on one chip. So my summation is that the SN9C236BJ6 is a 2MP camera version. But with so little data freely available, you could only be left a bit frustrated.

Exhibit 16 – CH1314 Exposed

The second largest chip, is this one, 8 pins a CH1314. I was unable to find any data here, but was expecting it to be a USB driver (a bit like the CH340G), but no luck here either …!

Exhibit 17 – Sundry others …

The balance of the passives and other devices of no real interest the 65E9 is just a BJT and the A701 perhaps some form of voltage regulator ..

.
Well that's about all there is to see inside the Andonstar 2MP microscope. Reassembly is the reverse of what we have done here, I would re-apply the hot snot, and be careful with those brass pins and the LED wires.. sadly though no reassembly for our microscope, with no data available,  and no discernible faults in the cabling, connectors or wiring, we're left with the daunting task replacing a 40 pin chip, on a tiny board with no real confidence that the problem would be fixed...

We really enjoyed using the Andonstar Microscope here at NoYoo, and some time soon we'll be on the look out for a new one. In the meantime we hope you enjoyed this look inside a piece of interesting technology.. attached below is the schematic of the USB cable, one interesting piece for us was the junction of the blue and black wires back in the PC USB connector. Interesting way to use 6 wires in a 4 wire connector..



Schematic of the Andonstar USB cable ...

As always your comments and questions are always welcome.. all the best ..