Discrete Opamp Open Design

[bcarso]

My cam is pretty limited for magnification, but it's a few years old so who knows what's out there. But there is only so much that can be done without good purpose-built optics.

[jneutron]

Originally Posted by vacuphile

I always work small parts under a stereomicroscope, and I can tell you, 40x is way too much. 4x magnification is more what you'd want. Look for second hand buys of a good brand, and it won't cost you a fortune. One of the best investments in workshop tools I made.

I agree with 40 being too much.

I use one that varies from 7 to 21, and another from 10 to 60. Most of my work is at 7. Whenever I have to solder under the scope, I refrain from drinking any coffee that morning.

I use high mag only when I need to really look at something close. But I cannot do most work at the hi mag. The only exception to that is watch repair, sometimes 7 just isn't quite enough.

Originally Posted by S.A.G.

A good alternative for a stereo microscope could be an USB microscope, see:

Dino-Lite-- Digital Microscope

Essentially a high magnification real time video camera. it takes just minutes to get used to work watching the PC screen instead of the real circuit board directly. I've learned this from our ECM that routinely does reworking jobs on very hi-tech boards.

Regards

Giorgio

I used one of those, it's really amazing how high those things magnify. But I have to be honest, nothing beats the stereoscopic vision. I find the depthing invaluable for small work.

jn

[bcarso]

Originally Posted by jneutron

I used one of those, it's really amazing how high those things magnify. But I have to be honest, nothing beats the stereoscopic vision. I find the depthing invaluable for small work.

jn

Depth perception is a good point.

[vacuphile]

Originally Posted by jneutron

Whenever I have to solder under the scope, I refrain from drinking any coffee that morning.

jn

It's Zen.

[dchisholm]

Originally Posted by qusp

. . . I didnt mention the need for 40x, that was dchisholm. . . .

I don't think it was me. For short tasks - like replacing just a 0805 resistor or SOT23 transistor - my tri-focaled, super-annuated eyeballs can often get by with just some strong light. My usual practice is to work SMT under a standard office magnifying lamp. Don't know the magnification; I got it at a yard sale or auction several years back. I wouldn't want to go more than about 1 step smaller than 0805/SOT23, though.

I also have a couple of surplus lenses from old copiers that give about 3x or 4x magnification. (E.g., 180mm focal length f/5.6) The image is large enough and the range of focus deep enough to look with both eyes and get good depth perception. The working distance is about 6" so I'm not bumping components as I move it over an assembly.

When I had a job there were a few times I used a stereo toolmaker's microscope to look for manufacturing defects. It's amazing how much more you can see with those things, even compared to a small desk magnifier - almost like the difference between troubleshooting with a Simpson 260 versus a Tek 465. But I can't imagine doing re-work, much less assembly, under that kind of microscope.

Dale

[dchisholm]

Originally Posted by bcarso

My cam is pretty limited for magnification, but it's a few years old so who knows what's out there. But there is only so much that can be done without good purpose-built optics.

I have a "P2V" USB webcam from IPEVO (see http://www.ipevo.com/prods/Point-2-View-USB-Camera ). It can auto-focus down to about an inch on an object that's essentially planar. The software application can do digital zoom up to 3x.

The atch image is a standard DIP package and 1/4W resistor on a solderless breadboard, from about 1.5" and 3x digital zoom.

I think I paid US$60 about 2 years ago. The company runs specials pricing, package deals, etc from time to time. There's now a 2x clip-on lens for it with built-in light that I haven't tried.

Dale

[qusp]

Originally Posted by dchisholm

I don't think it was me. For short tasks - like replacing just a 0805 resistor or SOT23 transistor - my tri-focaled, super-annuated eyeballs can often get by with just some strong light. My usual practice is to work SMT under a standard office magnifying lamp. Don't know the magnification; I got it at a yard sale or auction several years back. I wouldn't want to go more than about 1 step smaller than 0805/SOT23, though.

I also have a couple of surplus lenses from old copiers that give about 3x or 4x magnification. (E.g., 180mm focal length f/5.6) The image is large enough and the range of focus deep enough to look with both eyes and get good depth perception. The working distance is about 6" so I'm not bumping components as I move it over an assembly.

When I had a job there were a few times I used a stereo toolmaker's microscope to look for manufacturing defects. It's amazing how much more you can see with those things, even compared to a small desk magnifier - almost like the difference between troubleshooting with a Simpson 260 versus a Tek 465. But I can't imagine doing re-work, much less assembly, under that kind of microscope.

Dale

my apologies, it was grhughes who first brought it up in post #2726, it seems you and I are both on the same page.

@grhughes: have you actually worked under such an instrument? I can understand it maybe for checking much more complex work than this, but never working on anything

[grhughes]

No, I've never used one to solder a circuit board. I have used one on watch and clock parts to situate tiny screws. I'm in my early sixties and have slightly astigmatic vision so I want an instrument that can adjust out astigmatism. I will try to 5x visor first before I opt to buy a stereo microscope. The 3d depth perception is important so I believe trying to hook up my Olympus EP2 camera with a macro lens won't cut it 3d wise. It takes great 2d pics and movies but that's it. There are some good deals on ebone for stereo microscopes with digital camera that are firewire or USB compatible. There needs to be a comfortable working distance between lens and circuit board for drag soldering. And of course the board has to be kept absolutely horizontal, securely clamped down and the part glued down or you chase the part around with the tip of the iron. On a thru hole board the part is kept captive by the holes and you can orient the board any way you want to solder it. Just trying to glean as much info as possible and appreciate all comments. Ray

[Kindhornman]

Ray,
You need to get out of that cubicle more often....... Just kidding. I would think that the visors are the simple way to go for now. I also don't have the vision I used to have and it isn't fun when that happens. With the visors that I know of some even have interchangeable lenses for different magnification and some even have little led side lights on them for lighting up your subject. What I like about the visors is I can still wear my glasses under the visor and work with them on, that way you have your own correction for your eyes. I can only imagine the problems with a microscope having used those long ago in a medical lab setting, nice to look through but you pointed out the room between the lens and the work piece could be rather tight. Perhaps Qusp, my buddy can chime in on that one? With the visor you wouldn't be so locked in to having the board needing to be perfectly horizontal and could use one of those cheap hobby vises to hold the board and allow you to change positions as long as the part was stuck in place first.

Steven

[grhughes]

There is also the issue of heat sinking transistor leads while applying heat to the pad and part appendage. On a thru hole board I use hemastats to heat sink each transistor lead to prevent heat from traveling into the transistor and doing damage and pinching a SOT transistor with a hemastat will unglue it from the board. Also leaving the hemastat pinched on the narrow part appendage could make the solder joint a cold joint if pressure isn't applied very evenly. So I have to re-think that. SOT is really meant for reflow soldering not drag soldering with a hand iron. You young guys may be able to do that. Just my observations. One does what is comfortable! Ray