3DS Shuts Down Completely when Inserting Game Cartridge

Hi:

I bought my son a New Nintendo 3DS 2015 NON XL Version. After a few months, some pins on the game card reader broke. I bought a replacement game card reader and installed it following the repair guide on this site and successfully changed the game card reader.

The problem I have now is that sometimes, when I insert any game card the 3DS completely powers off and won't turn on until I remove the game card from the reader. Also, if I insert a game card on the reader and try to turn on the console it won't turn on.

This doesn't happen every time but is a problem and don't know what to do to resolve the issue. Hope you can help me with this problem.

Thanks in advance...