I've been looking for something cheap to inspect SMD solder joints, ideally I'd like to eventually get a proper binocular microscope but at the moment it's a bit outside my budget. I'm happy doing the soldering by eye so I only need to inspect the joints. I've already tried the generic cheap Chinese USB microscope and whilst it was ok for reading part numbers and inspecting PCBs, it's pretty much useless for inspecting solder joints. The small aperture requires a lot of light to see anything, which just reflects off the shiny solder and overexposes the image sensor. The LEDs are also poorly diffused and reflect off the plastic ring and are visible on the image, the update rate is also pretty poor and the stand is cheap rubbish that doesn't stay in one position. Even worse, it's fixed focus so the only thing you can change is the zoom level and distance from the subject so I've sent this back.
I don't need it to be USB necessarily so I've just been looking at handheld microscopes and magnifiers. I've found this illuminated loupe which is designed specifically for electronics which seems the best option, or some suggestions I've seen in past threads on the subject were a micronta handheld microscope (or modern equivalent). Are these still the best options or is there anything else I could get within the ~£10-30 range?
I didn't originally start my reply with this, but afterwards I inserted this at the beginning of my reply:
1. You can't use something handheld, you will need both hands.
2. If you can't take pictures, you can't share your work (or problems) with the internet.
3. Close-circularly lighted loops (like contained on the microscope I am recommending below) sometimes make it difficult to read the printing on ICs. You'll need a polarizer (not gonna happen for cheap) or an external light to overcome this problem in any case.
The best option I'm aware of is
this USB microscope. I have had two of these (I destroyed one trying to repair a problem -- more on this in a second).
They work right out of the box with any camera software; you get a decent image but with normal FPS (~ 25). The stand is flexible and can be mounted or swapped out. The zoom control is very, very nice and smooth.
The only downside so far is that the strain relief which holds the cable in doesn't seem to be fixed or screwed in properly (it's a plastic loop with screw, directly on the inside of the case) all the time. Both of my two units have suffered from this problem. It would be easily fixed by opening the case yourself and putting a dab of glue on, or screwing tighter, or whatever. In any case, what happens is the USB shield gets a little exposed (but it's not connected on the microscope side anyway, the designer of the unit assured me).
I've attached some pictures. The first three show my normal use: taking pictures of or identifying parts. The second two use the microscope's actual physical zoom lens, which is only usable for a tiny portion of the zoom travel at the end. As far as I can tell, the "zoom" is simply the magnification of the video on your monitor. This seems bad, but to me it seems totally sufficient.
This album is my most recent usage of this device: to take original photos and then do SMD soldering of the conversion of a
Direct TV SUP-2400 converter into a general purpose down-converter for SDRs. It only contains the originals as pictures.
Note: I am lighting these pictures with a bright, external light. This is something you will want if you use this microscope. Many times, the internal lights are sufficient. Many times, they are not. It's also nice to have lightsource you can move around so you can make sure to view things from every angle, but more importantly, when you want to take pictures of chip markings. Sometimes direct over headlight makes it impossible to read chips. The last two images are an example of this. The first is using the microscope's light, the second an external light.
Overall, I would recommend this device. The seller's engineer who contacted me this week said that this problem of the cable strain relief coming undone is rare (claims to sell 800 units a week, less than a handful of strain problems total); that they are working on a new stand of some sort; and that both of my two units are refunded/returned under warranty (despite being a year old). I was therefore relatively please with this level of customer support also.
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