Barely visible defects, but already irreversible deformations
With the vast selection of defective test objects, it was quite easy to find headers whose contacts were not visibly burnt yet, although the header had already been irreversibly damaged. The top row shows the 4 sense pins, followed in the middle by the six 12-volt pins (image is cropped), and below them the six ground pins. And beware, right at the bottom in the middle, we see the locking mechanism for the Cable Plug!
We can see that the base is already significantly burnt and the locking mechanism has deformed so much that it was difficult to remove the Cable Plug. Also note the bubbles in the plastic (please click to enlarge). The greatest visible damage on the header is in the recessed area of the board between the header and the locking mechanism! However, it is located below the ground pins and not at the 12-volt ones, which are prone to burning. We will see this more often, but none of the people I have asked could really explain it.
Now let’s take a look at the back with the through-holes of the pins as a wire with a bend up to the board. Here, too, we can already see the first signs of dissolution, which the normal user cannot see with the naked eye on the soldered header:
Headers with “light” damage and 1 to 2 burnt contacts
Here, it’s one of the middle contacts that has already “disappeared”, and the two contacts to the left of it have already been so hot that the plastic around the through-hole has melted!
This connector was extremely difficult to remove, but at least the locking mechanism could still be released to a reasonable extent. I used the microscope again in multi-light mode, as it makes everything look much more vivid:
This can even be viewed as a height profile because it really looks like craters on the moon.
I will skip the pin through-holes now, because the back now looks just like the bottom.
- 1 - Introduction, Important Preface, and the PCI SIG
- 2 - Material Analysis with a Key Finding
- 3 - Damage Level 1: Barely Visible or Minor Damage
- 4 - Damage Level 2: Moderate to Major Damage
- 5 - Pin Width, Twisting, Positional Tolerance, and Clamping Surface
- 6 - Summary, Overview of Most Causes, and Conclusion
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