SD card pins melted on Pi 4

Question

I'm running a Pi4 with a 32Gb SanDisk Extreme SD card and essentially just AdBlock. The board is powered by the official USB-C plug and has a passive cooling case around.

Since last week my system kept crashing. I finally managed to capture the logs:

Jul  5 12:54:03 raspberrypi kernel: [ 3227.388458] blk_update_request: I/O error, dev mmcblk0, sector 534240 op 0x1:(WRITE) flags 0x103000 phys_seg 1 prio class 0
Jul  5 12:54:03 raspberrypi kernel: [ 3227.388484] Buffer I/O error on dev mmcblk0p2, logical block 220, lost async page write
Jul  5 12:54:03 raspberrypi kernel: [ 3227.388748] mmc0: card aaaa removed

I checked the SD card and there was some white stuff around the SD card pins. Once I removed that carefully, I realized the pins look kind of melted.

I guess there's not much I can do without soldering equipment, except try warranty? We had a heat wave, so I expect the average room temperature plus load caused this, but it's still puzzling to me how.

Can this be fixed / is it worth it to try to fix myself, or should I see if the manufacturer will replace it under warranty?

Note: There's no humidity or water nearby. It was just really hot the last few days. The device isn't 3 months old. If it is corrosion though, can I fix it somehow?

Answer 1

It looks like you got a board which has been through rework after production. The SD card slot was not properly soldered after reflow, so it was re-soldered manually, and manual soldering doesn't look as pretty as reflow (and has a higher failure rate).

The white stuff around the pads is the solder flux which whoever who did the repair didn't bother to clean. It's not harmful though, the failure is most probably due to soldering temperature being too low or movement/vibration during hardening of the tin, which resulted in a crack making poor contact.

It's also possible that the board is refurbished, but normally refurbished devices are clearly marked as such when they are sold.

In any case, there is no way this is a result of ambient temperature.

If the board is still under warranty, you should definitely send it back. Only try to fix it if you can't get a replacement, though the fix is not hard to do: heat every pin with a soldering iron, and then try to lift it with a needle: if it moves, resolder it again. If that doesn't help, the copper trace on the board is cracked as well, and the board is beyond repair unless you a quite skilled (and for a 50$ board I wouldn't bother).