Other then the nicely plated gold pins in the bottom right. I'm also not sure about the pins on top left. They look like an odd connection housing of some sort. But the picture doesn't show, but they look really silvery in color. Almost too much so. Could they be silver plated? Or the rectangular grey boxes? Don't they have silver?
See anything on here worth keeping?
- Thread starter Rreyes097
- Start date
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It is probably Tin.
Easy to check, put them in HCl.
The grey boxes say R which means resistors, unlikely to contain Silver, bad as resistor material.
Thanks! I figured but had to get a second opinion. Couldn't remember what the grey ones were.
R is Resistor
C is capacitor
F is Fuse and so on.
It is simple so how can you not remember ?
And just in case you meant these.
They have numbers on them and producer.
Google will tell you.
Because I forget things. And have limited exposure to those types of materials so the date is unfamiliar. But thanks for the information. I was just really showing this board off in a way. I didn't see much to depopulate it for and so i wanted to stimulate conversation and discussion about it. It's those conversations, that helps to retain the information brought on by posting. Because if I don't know then chances are that someone doesn't either. I don't always know what parts are what because I really don't know much about the miscellaneous pieces that don't have the pms I'm looking for. So I haven't put much thought into the parts that don't have the good stuff! 
And it's not that I don't remember what they are either. I just sometimes don't know if each design of resistor or capacitor have different precious metal content.
And it's not that I don't remember what they are either. I just sometimes don't know if each design of resistor or capacitor have different precious metal content.
macfixer01
Well-known member
There are the 3 white relays that Yggdrasil already mentioned, and also the 3 red relays on the right side (labeled K100,K200,K300). All of those will have some silver or gold plated silver contacts inside. There are 6 white surface mounted LED’s at the top-right corner which should each contain a single gold bond wire. Those would usually be labeled with a Dxx number for diode, but in this case are labeled for their function showing that voltages are present, so V100, V101, etc. To the left of that black connector there are 2 different types of IC’s, and the other little black device between them that has 3 pins on one side and a metal tab on the other side, is a transistor. You have a few of those transistors spread around the board. Other than that you also have several of those tiny little brown MLCC capacitors (labeled CXX) which you should save because they contain silver and may also contain palladium.
I have an exercise for you.
Take the board you are asking about.
Hold it in front of you, and start describing it to yourself.
Then you start describing the components on it and guess why they look like they do (Remember design comes from function in most cases)
Then look at the board again and see if there are some marking that can give a hint.
If it fails to reveal itself, start Google and search for any numbers on the component.
After this excersice you should have worked up somewhat understanding of the components.
macfixer01
Well-known member
Yes it’s definitely more challenging when you introduce several types of similar-looking surface mount components, especially with minimal labeling. The board labeling can be helpful sometimes but can’t always be relied on so it’s good to recognize components by sight. As I’ve said before, the silkscreened part labeling is left up to those that created the board. If for example they don’t necessarily want third-parties servicing their boards, they don’t have to label anything since assembly is often fully automated. They are free to follow industry conventions or not. Integrated circuits can be labeled ICxx or Uxx or recently I’ve run across a few labeled Zxx. Why the IC’s are labeled ULxx on this board I have no idea? I have to wonder about the larger 2-pin components labeled RDxx? Obviously they’re made to handle some current, I’m guessing those are rectifiers (diodes) which would usually be labeled Dxx or CRxx. The transistors are apparently labeled TR which is not unheard of, but would usually be Qxx. The Lxx labeling for inductors is common. I see a couple 4-pin optocouplers labeled OPxx which can also be labeled the same as the IC’s sometimes. Lastly the connectors seem to be labeled Mxx but the industry standard is generally Jxx.
Actually I just realized the devices I called transistors in the first photo you posted may have actually been 3-pin voltage regulators, since they’re all labeled Vxx? VRxx would’ve been more common, and could also be confusing because of the same odd Vxx labeling on the LEDs. I was looking back at them since I was going to mention that both designs are common for SMD transistors. In the first photo they have 3 leads plus the metal collector tab, but on this other board they only have 2 leads and the collector tab on the other side. They only actually need 3 leads total in either case, and one of those 3 leads would be connected to the tab internally. The larger collector tab can be used as a lead but also helps a bit with heat dissipation. Both types would be processed the same way so it doesn’t really matter, but may explain the labeling difference? I only mentioned it for visual recognition since you’ll find SMD transistors made both ways.
The orange parts "SCHRACK" are relays.
They contain silver contacts (about 80% silver). About 0.3 grams per relay.
The three "AXICOM" are relays also.
They contain gold plated silver contacts, but they are very small.
