Found Silver & Tantalum

I find that usually the circuit board is marked with the + sign, but you are correct a lot of them are not. You can't really go by the + sign on the capacitor either, as the + sign is on a lot of electrolytic capacitors also. If you take the time to educate yourself about tantalum capacitors, how they are made, the material that is used and where they are used. You can get fairly efficient at locating the type of board and then finding the tantalum capacitors on the board. I do have a background in electronics, electronics engineering degree, FCC license with a radar endorsement and twenty + years trouble shooting, identifying, isolating and fixing complex mechanical and electronic equipment. This was in my last "lifetime" and the old saying "Use it or loose it" is all so true! I like getting back into it, finding E-waste allows me to at least think about, what I used to do.

There are Tantalum capacitors on low grade boards, not usually but here is one example. These two little "muster yellow" epoxy "gum drops" weigh only .2 grams total. They actually came off of a old color TV, didn't expect to find them. I was scraping some old low grade boards, harvesting the coils, chokes, IC's and transformers. There in the middle of this TV board was these two "K" tantalum capacitors.

Here are some more pictures of low grade boards that I have found these epoxy tantalum capacitors on., Going from left to right, the tan board is a thermostat board, the middle green/green is off of industrial machine monitor (B&W) and the right one is off a chemical making control board. All three are low grade boards and made in the 80's and early 90's. The tan board only had two caps, the middle had eight black caps and the one on the right had three red & orange ones. It literally takes only seconds to snip these off of the board. I do use magnifying glasses (5X magnification) that make this job much quicker. Takes much longer learning what a tantalum capacitor is and where they can be found!

I too have started in on the tantalum hunt recently and your spot on when you said that they are nowhere near as prevalent on the "newer boards". One little thing that I have noticed that applies across the board is the color MUSTARD YELLOW. 90% of the epoxy Ta and even the ones I call bricks are mustard yellow in color. Now the tear drop ones do come in an assortment of colors but with those the shape and the fact that everyone has a little kick in one of the lead legs. Anyway that's my little tip for the easy to find ones.