Maxim has developed a reputation for announcing many interesting chips but backing them up with very limited (or nonexistent) production quantities. So I, and many of my acquaintances, are wary of using Maxim parts even in hobby projects. My own rule of thumb is that if Digikey and/or Mouser don't have substantial quantities of a Maxim part *in stock*, I look for an alternative. FWIW, both Mouser and Digikey only have a handful of MAX1874.
I'm using 10X wide field eye pieces and .7 to 3X zoom so the overall magnification (with the 0.5X) is 3.5 to 15X. This is a nice range for working and if I need more magnification I can take off the Barlow.
I did a quick measurement on my scope. I have a normal working distance of 10cm. Using a .5X Barlow increases this to 19cm. My Barlow lens is particularly long (4cm, even bigger than yours) but that still nets me a 50% increase in working distance. I find the difference between 10cm and 15cm to be really important when trying to solder.
I did a conversion of an aquarium air pump to vacuum (lots of instructions on the net for how to do that). I also found that the suction was too strong and added a valve to regulate the vacuum. A good place to find such valves is in aquarium supply stores. They are the appropriate size for air hoses and are quite inexpensive.
I did some experimenting with a sheet of acrylic and a laser cutter to create a stencil8 block. It is hard to get a really tight fit on the 2.5mm pegs with a laser cutter since the holes are not nearly as precise as they would be from a mill. So there is a little play in the pegs when you put them in the plastic block. However, the 2.5mm holes which were milled into a test PCB were a more precise fit so when the board is placed onto the pegs the whole thing is very stable. I also did some tests of cutting appropriate holes into a Kapton stencil with a laser cutter. There is still a very small amount of movement in the stencil but overall I think the alignment is very good. A metal stencil would probably work better since it would be more rigid. I still have to do a complete board including putting the paste down and reflowing but I think that a laser cut plastic block and Kapton stencil is a reasonable, lower cost, way to do the stencil8 process. It is certainly not going to be as precise as a milled aluminum plate or a metal stencil but I think it will work pretty well.
You definitely don't want a scope which is intended for biological samples with illumination from below. You want an inspection scope. One model which was commonly used was the Bausch and Lomb Stereozoom series. They were made for 40 years or so and are still widely available on the surplus market. The basic Stereozoom head is .7 to 3X zoom. There are various eyepieces you can choose from. The most common are 10X so that give you an overall magnification of 7 to 30X which is a good general range for electronics work. If you add a 0.5X Barlow to the bottom then you get double the working distance with an overall magnification of 3.5 to 15X which is still good for most work. You also need to choose some sort of stand. There are various choices but the best is a "boom" stand which is two arms which allows you to move the microscope head up and down as well as in and out so you can cover a wide area. This allows you to work on larger boards or other equipment. Sometimes, if you only have a fixed stand, you have a hard time getting larger work under the scope. You can find similar scopes new from places like Amscope, etc. Hopefully, this gives you some idea of what to look for. If you get the right stereo scope, you will be amazed at how much easier small work is. There is a visual feedback loop which makes all your hand movement way more precise.
Hi, Arhi- Hmm, I'm not sure I can help you much with finding a way to attach an auxiliary lens to your microscope. The ones I'm most familiar with (including one from AmScope) have threads at the bottom for attaching accessories like lens. The only thing I can suggest is that you try to find something like this lens:
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which I found at a local surplus store. It has a ring clamp to attach to something but I don't know what it was originally designed for. -scott
Those of you who work under microscopes a lot probably already know this, but it is worth mentioning just in case: The trick to getting more working distance (the distance between the bottom of a microscope and the workpiece) is to use a 0.5X auxiliary lens (sometimes called a Barlow lens). This is a lens which screws onto the bottom of the microscope and changes the overall magnification by 0.5X. Other powers are available including those which increase magnification. When you cut the magnification in half with a 0.5X lens you almost double the working distance, which makes a huge difference when you are trying to solder. Most of the time, you still have plenty of magnification available with your microscope so the working distance tradeoff is a good one.
Although I don't think I need 100 LD1117s, I'll just say that I have bought other things from Asia Engineer, as have a few other people I know. We haven't had any problems so far. The prices are usually quite good.
Kit is on the way. I don't think there is any way I can use it without the miniprog3 to program/debug the chips but I will check it out for sure when it gets here. Thanks for the coupon code and I will certainly put it to good use. I'd be happy to report on it but perhaps it is best not to given your comment about cypress.
I have just started to get into the Cypress PSoC chips so I would like to have the coupon if it is still available. US shipping wouldn't be too bad for me. -Scott
I think there are probably two issues. One is that the stereo microscope makes a huge difference in how well you can control your soldering iron. The magnified visual feedback is the key. Secondly, if your Radio Shack iron doesn't have feedback controlled temperature (with a sensor in the iron) then that is another likely culprit for difficult soldering. There are quite a number of decent irons from China (Ayoue for example) which are not very expensive. Take a look at some of the Hakko 936 clones. I think you also might find that those have somewhat shorter distances between grip and tip although I haven't measured one to see.
