Nintendo Switch is killing card readers?

Hello you lot,

First time posting here, and very happy to be part of the community. Context: I’m a new boy, have a load of Switches, have repaired the easy ones and am working through the more complex cases.

This one has me stuck.

Switch A - fully working
Switch B - no power
Switch C - no power

So I fixed Switch B by changing the USB port. It came back to life, but has the issue of not reading game cards. At all. It would acknolwedge a card was in there, but couldn’t read it. I tried this with two games. Same issue.

So I swapped the card reader (the entire board) from Switch A (which I know works fine) to Switch B. Same issue. I also tried the board from Switch C (unsure if this was a good one), but same issue. I also took the card reader from Switch B and put it into Switch A, and it wasn’t able to read cards.

Soooo… defective card reader in Switch B AND possibly a motherboard issue in Switch B.

However… now I’ve put the original card reader back into Switch A, Switch A no longer reads cards! Bonkers! I’ve checked the pins on the male and female parts of the ribbon connector on the game card board, and they all look fine. I’ve cleaned them and reconnected, same issue.

I’ve even used a map from YouTube (search for “How to fix Nintendo Switch game cassette reading failure” with a thumbnail that says “This map helps your switch error” and a ‘scream’ emoji) to check the traces on the ribbon for Switch A are intact. Which they are.

So I have NO idea what’s happened. It could be a damaged pin somewhere, but all look good under a microscope. It could be the game card connector on the motherboard of Switch B caused some damage to the card reader from Switch A, but (again) the traces all appear fine.

Next step - open another switch and move the card reader into Switch A to get that one working again. I’ll report back. But I wanted to at least start this thread as I couldn’t find anything like it online. Not a sausage.

Thanks in advance for your help, team. Really appreciate it.

Ps. More photos and detail available. Just let me know what you’d like.

Ed

Naughty Ed. Naughty!

I forgot some important information.

Switch A - I had to swap the joycon connectors on the main board for this device. AND I also swapped the fan connector and removed the diode just next to it. The LCD connector is also broken, so I’m awaiting a replacement for that. So heat has been applied in the general area of the game card socket on the main board. This is probably VERY useful information. My bad.

Another update:

I’ve taken the card reader and put it into another Switch, and it’s working fine. Therefore, Switch A and B must have faulty motherboards.