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Beware of old AntiStatic foam
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amyk:

--- Quote from: intabits on March 21, 2021, 11:44:49 am ---It looks like the pins on these ceramic packages are not part of the leadframe, but separate pieces that are welded(?) to the frame. I hope they are welded, rather than soldered, so that they won't come adrift when I solder them to the socket.
--- End quote ---
They might be soldered with high-temperature solder. On the bright side, if they do come off, you're left with a DFN-40 :-DD
Berni:
Wow it does completely eat away the thin part of the pin.

Would have never thought that decomposing antistatic foam could be this corrosive. Even most RTC battery leaks are not as aggressive as this.
intabits:

--- Quote from: tooki on March 21, 2021, 06:07:24 pm ---What were these chips, and their foam, stored in, and under what conditions?

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They were stored in a parts draw cabinet. Admittedly, in a room exposed more to the outside air, so with higher humidity.
There's no other black foam-mounted parts in the drawers to compare with, but other parts in the drawers show no similar corrosion, and other chips stored in aluminium foil over styrofoam in the same environment are all OK. So it seems the foam (possibly plus humidity) caused it.



--- Quote from: magic on March 21, 2021, 07:09:03 pm ---Beware that inserting the bottom pins of a female socket into another female socket will ruin the latter.
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I wasn't aware of that. Also, the pins on those sockets are easily broken off when straightening a bent one. The leftmost one in the photo is already bent.

I don't need to insert them into any standard socket, I just want to connect them up to some sort of demo/display system.

So I'm starting to lean towards the idea of a PCB with header pins, like an Arduino shield.
I'd just cut off the thin parts of all the pins, and just "surface mount" the chips onto traces going to the header strips.
If the headers become damaged, they can be replaced without ever touching the chips. And removing the chips would be a little easier if that ever became necessary. And while I'm at it, put basic items like bypass caps & a crystal on there as well...
magic:
They simply are thicker than male pins that normally go into those sockets.
Also, male pins have two ends and the wrong end is too thick as well.
Surprising complexity for such a seemingly simple connector :)
Ian.M:
This paper on gold/tin solder bond strength may be of interest: https://www.osti.gov/servlets/purl/1142490

Look at Aries 40-600-10 flat pin headers which are readily available.  If you can find stock, Aries 40-600-11 would be even nicer as that's the gold plated version.  If the old pins were cropped, sanded and lightly tinned and the inside face of the fork terminals on the header was similarly tinned, after they were formed to fit the slight package over-width due to the old pin remnants, it should be possible to extract the individual pins, put them in a jig (e.g. a turned pin socket that's been oversized by reaming with a 0.55mm HSS drill bit in a pin vise) for alignment, and sweat them onto the well fluxed pin stubs.
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