This started when I was replacing my fans with 12 V Noctuas wiring in a 24 V-12 V buck converter for the three fans I replaced. The two other fans (blower and motherboard fan) read 0 V which led me to the fuse on the motherboard I think.
I was only reading 2.5 V on my "always on" fans and wanted to take a deep dive. I found the schematic for the Ender 3 Pro here (I have a 4.2.2 Board). When I probed the fuse, I did not read a short on my multimeter, but the display on the buck converter I have attached turned on.
For the hell of it, I attached a wire across the fuse and it sparked, but the display on my buck turned on for a second, not sure if I caused a short if the fuse is broken (which it seems like it is), and what to do.
I think the 2.4 V drop I measured over the Fan+ (always on fan) was due to the diode voltage drops from the protection circuit.
Any advice would be appreciated (minus buying a Prusa or something better, I'm aware) since I'd like to make the printer work with the buck converters and Noctua fans I bought following this video:
Showing F3 on the board:
Creality Board 4.2.2 and 4.2.7 Schematics
Someone else's similar issue I found on a Reddit post "need help ! ender 3 pro fans not working , motherboard : v4.2.2".
Note: I have cross-posted this on Reddit, but I could really use the help!
