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| Digi-Key Sold Me 7 Year Old Capacitors |
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| Bud:
I recently got a bunch of jelly bean logic ICs from Digikey in PDIP package, all of them of Texas Instruments brand with date codes 2018÷2019. The bizarre thing was all of them had leads blackened as if they oxidized. It was unusual for such freshly made ICs to have that. The even more weird thing was the leads were only dark on the outside of the leads, the leads sides facing each other looked normal. They came in tubes. Search for TI PDIP leads finish did not produce any recent hits. I did not speak with Digikey on that, just used an eraser to clean the leads before soldering as i wanted to go ahead with my project. |
| mcovington:
One detail: Nichicon is one of the most respected brands of capacitors, as I understand it. Maybe theirs last longer. I'm currently trying to decide whether some 15- to 30-year old capacitors in my stock should be tossed... |
| alank2:
I really like Digikey's search engine, but their customer service disappoints me nearly 90% of the time I bother to contact them. They almost always want to tell you it is your fault. They love to tell you that if you didn't put it in the order notes that it is your fault. Order a part and get a date stamp that is fine Order two more and get one that has an older date stamp with errata on it. Call them and they will say "you didn't ask for the newer one, it is your fault". Mouser on the other hand has always had a good attitude with me and is quick to solve problems. |
| chickenHeadKnob:
--- Quote from: Bud on September 01, 2019, 02:20:18 am ---I recently got a bunch of jelly bean logic ICs from Digikey in PDIP package, all of them of Texas Instruments brand with date codes 2018÷2019. The bizarre thing was all of them had leads blackened as if they oxidized. It was unusual for such freshly made ICs to have that. The even more weird thing was the leads were only dark on the outside of the leads, the leads sides facing each other looked normal. They came in tubes. Search for TI PDIP leads finish did not produce any recent hits. I did not speak with Digikey on that, just used an eraser to clean the leads before soldering as i wanted to go ahead with my project. --- End quote --- There is a situation that can occur with tin plating I have heard of but not seen myself: micro motion fretting corrosion, small wear movements of say the pin legs against the tube leave a black surface. That would explain why only the outside of the pins show it. Was any tarnish on a surface that wasn't in contact with another surface? Samtec pdf on the phenomena: http://suddendocs.samtec.com/productspecs/fretting-corrosion.pdf |
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