Missing R46 & R49

[dannyt66]

Hi All,

My Raspberry Pi Model B (Samsung chip) suffered damage to its SD slot, causing a repair to be required. I have replaced the SD slot with another, and tested all pins are correct and no shorts have occurred, along with manually connecting the SD detect lines due to the new slot lacking this functionality.

However, when inserting an SD card and attempting to boot, I get the dim ACT light and no response from the Pi. I have checked the FAT portion of the SD, and all appears to be correct so I am willing to assume this is something other than the SD, although please let me know if you believe this not to be the case.

Upon inspecting all my work, I have noticed that R46 and R49 appear to be missing from the board, and I can see traces leading from these two resistors leading to the SD slot, then onto the SoC area. Upon looking at images of other model B Pis I can see these resistors present in these, and am wondering if this could be the reason my system is not reading an SD card? I cannot see any signs of these resistors being pulled off of the board, but please see attached photos to check if I am looking at this incorrectly.

R49:


R46:


SD area overview:


Top board overview:


The bottom pad of the SD has also been lifted during the desoldering of the last slot, but I am led to believe from reading that these are for write protection only and in fact do nothing on the raspberry pi, not even being connected, so I am assuming that this is not the cause of my issues.

Thanks in advance,
Dan

[gordon77]

They look like they connect to DO (Dout) and DI (Din) on the SD card so I would suspect so

[dannyt66]

My thoughts also, I've checked with a friend who got his B the same time I did, and his has these two resistors. As a last ditch I might try shorting them out of the circuit, as I have a B+ and I just wanted to fix this one for a laugh really, so it doesn't matter much to me if I fry it.

Thanks,
Dan

[rpdom]

I lost one of those resistors while doing the same repair on one of my model As. I've replaced the resistor with the correct value (a slightly larger sized one though) and it is connected. The Pi still won't boot though

Pi.png (63.92 KiB) Viewed 1037 times

[dannyt66]

That isn't good The schematics say they are all 33Ω resistors, so I am going to attempt to make one. Wish me luck! I'll post back if I have success.

[rpdom]

I hope you have better luck than I did

It was lucky that was my spare A

[dannyt66]

Well, after trying I can report failure. I struggled to solder to the pads (a combination of too large a tip and too bad eyesight), and managed to lift the pad for R46. I had managed to solder to the trace, however this was too weak and it broke. In the process of attempting to fix this, I managed to desolder R47, at which point I shall admit defeat. With better tools and skill I could probably have managed this, but I shall finally declare this Pi dead.

Thanks for helping me out everyone, guess my B+ shall have to live in server solitude still.

[piguyang]

I have also been defeated this way. I slipped with the solder and removed the r49 resistor. My r49 pad lifted and one of the read/writes did also. I hate to toss this pi being still good. I wish i knew a better way to attempt another fix.