Summary

I do realize that the chance of someone doing the exact mod is slim, so this post should be taken more or less as an inspiration how to refurbish an older digital microscope with a modern HD camera.

Some microscopes such as the Motic 143 have build in USB camera. While the actual microscope can be considered still "new" being made just a decade ago, that is not the same for the camera. Even worse, most of the time there is no way to make such cameras work on windows 7 or 10. But even if you somehow succeed, the picture quality may be still disappointing by today standards.

The mod is really easy - we just swap the old CCD imager with the guts of a good HD CMOS USB camera. A great source for such chips are web cams - because you can pick one that is supported by recent OS and you can test it beforehand to see how it looks. You practically need just the iside PCB with the CMOS chip, no lenses, as we will reuse the optics of the old camera. Also save those mini screws - handy!

The only downside is that common web cams are 1/2.5", while the CCD on the old microscope is larger (looks like 1/1.9"). That means the new cam will show a center crop of the image. Well, we can't have everything and maybe someone will come across webcam that has 1/2" or larger chip.

I choose the Microsoft lifecam HD3000 mostly because I had one at hand (bought it for $5 in a garage sale), it had reasonably sharp image and 720 HD video and it was recognized by all my computers on W7 and W10 without any need of drivers when I tried. (The HD3000 supporting software however can't be installed on windows 10 even if you tried, but no harm done, the windows catalogue has the correct driver). The camera has also small footprint which is exactly what we need. Another good candidate would be lifecam studio.

NOTE: There is a remix for Lifecam STUDIO as well.

Also breaking it appart was really easy as the camera popped up open just by using my fingernails revealing just few screws holding the PCB. Thank goodness for cheap manufacturing. So instant hit on all accounts.

Wiring is easy as well - both cameras use usb and every USB cable conforms to the same color coding - so it is really just cutting the new web cam wire and then attaching red to red, white to white... make sure you recognize which black wire is the outer shielding and which is the actual minus wire because there are usually two of those. I used a small piece bread board PCB to attach the wires to each other.
A top of my microscope camera housing had a led and so I simply wired it through a small connector to the red and black wire of the USB wire through 1Kohm resistor.

So for Motic 143 and Lifecam HD3000 I did all the job for you and designed the exact correct bracket. For other combination - use it as an inspiration, get digital caliper and start measuring!

A microscope will have an IR cutoff filter (cyan colored) in front of the chip - depending on the web cam such filter may be part of the lens. Anyway without the IR cutoff the image would be washed out and colors will be off - especially green color of PCB would simply looks dirty bluish. The bracket has a place on the bottom to attach the original IR filter from the microscope.

Another tip: before assembly clean the CMOS and the filter with some optical fluid otherwise you may have dust blobs on it.

I was satisfied with the result. The image is in the same range like most of the 1/2.5" based digital microscopes that use similar spec chip. It gives clear, reasonably sharp image and good colors. Of course the better the CMOS is the better would be the result.