southafricanrob
Posts: 31
Joined: Wed Sep 18, 2013 12:54 pm

Damaged solder pads for SD card slot

Tue Mar 03, 2015 6:44 pm

Hi,
I dropped my pi with the SD card in and the SD card holder broke. I have got a replacement card holder but have noticed that 3 of the copper pads cracked off the board and stayed stuck on the broken holder. I can't see a line running to these pads on the PCB so not sure how / if possible to intercept the track to these pads to resolder the new card holder in place. 2 of the broken pads are the card detection on the left and the other is 1 before the card detection on the right.
Not a great pic but you can get the idea..
Image

gordon77
Posts: 4368
Joined: Sun Aug 05, 2012 3:12 pm

Re: Damaged solder pads for SD card slot

Tue Mar 03, 2015 7:01 pm

Comparing it to the image below were the bottom 2 attached to anything ? May not be required ?

And the upper 1 missing could to connected to r45 linked to it ?
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Last edited by gordon77 on Tue Mar 03, 2015 10:18 pm, edited 1 time in total.

jdb
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 2199
Joined: Thu Jul 11, 2013 2:37 pm

Re: Damaged solder pads for SD card slot

Tue Mar 03, 2015 7:05 pm

The bottom two pads don't matter - they are write-protect and not wired up.

The other broken pad is connected to R45 - see the wrecked bit of track still attached to the resistor?

You have two of the pads bridged with solder at the top - rectify this before attaching a replacement card holder.
Rockets are loud.
https://astro-pi.org

southafricanrob
Posts: 31
Joined: Wed Sep 18, 2013 12:54 pm

Re: Damaged solder pads for SD card slot

Tue Mar 03, 2015 7:13 pm

Thanks,
Are the top and bottom 2 not required to be connected (bridged in this case) for the pi to function? I assumed that if bottom 2 not then pin will think no card is present? And am I correct then that I could resolder the missing pad carefully to the R45 resistor?

jdb
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 2199
Joined: Thu Jul 11, 2013 2:37 pm

Re: Damaged solder pads for SD card slot

Tue Mar 03, 2015 10:15 pm

The card detection switch is ignored by the driver (or at least should be).
You can solder on to R45 to restore the trace but it's an 0402 component - you need a tiny soldering tip.
Rockets are loud.
https://astro-pi.org

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panik
Posts: 369
Joined: Fri Sep 23, 2011 12:29 pm
Location: Netherlands

Re: Damaged solder pads for SD card slot

Tue Mar 03, 2015 10:49 pm

jdb wrote:You can solder on to R45 to restore the trace but it's an 0402 component - you need a tiny soldering tip.
A bit premature maybe, but if the pad is beyond recovery you could cover 0402 R45 with a blob of solder and replace it with a bigger component. 0805 is probably just big enough to act as part of a mechanical bridge that connects directly to the pin of the SD card holder.

I've only been eyeballing it, but that looks doable if you have them laying around.
Microcontroller addon boards and software for Raspberry Pi A+/B+/Pi2:
- ARMinARM: ARM Cortex-M3 (STM32)
- AVRPi: ATmega32U4 & ATmega328 ("Arduino")
http://www.onandoffables.com

southafricanrob
Posts: 31
Joined: Wed Sep 18, 2013 12:54 pm

Re: Damaged solder pads for SD card slot

Wed Mar 04, 2015 8:18 am

Thanks panik. I've gone ahead and soldered carefully but alas still a dead pi. Only the red PWR led comes on which i gather means no SD card being accessed. Will check over my solder joints with a magnifying glass and try again!

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