Hello,
I bought this Switch a few weeks ago and have had a few issues arise.
I am no longer able to charge any of my 6 joycons and after opening it up and having it running i see that the Fan is not spinning.
I read that a dead fan could interrupt the flow of charging joycons but im skeptical
Im thinking of replacing the fans but i want to know if replacing the rails is also a good option to see if that might fix the switches charging problem.
I’m going through a similar issue… What I’ve learned is the fan can take the circuit down, there is a diode that goes bad and can ground the circuit, and there is an ic that goes bad and will also cause this issue. I’ll see if I can find some pics to help
So I tried to include a link but the forum won’t let me. Search the forum for “joycons don’t charge” I believe that will give you the answers you seek 
I was able to find it thanks!
Now i just need to find a PU chip as my board does not have the diode
hello. The diode is very litte but work. Did you find the diode and take off? Today it’s work to me.
I didn’t have the diode on my version not all of them have it and from the looks of it theres a chip that needs to be replaced and i am unable to find it anywhere