The PCB cabling harness on the Geeetech Pro B is very messy. Also the fan is very inefficient blowing across the PCB.
Therefore I created a cover that "clips" behind the PCB i.e. it uses the PCB to hold itself against the back strut. I also took advantage of a hole in the vertical strut - where you can push standard geeetech bolt (3mm) through to hold it in place.
The fan I used was not the standard Geeetech one, from a few posts I read, if you can cool the PCB more - you get better prints - so I bought a slightly bigger fan with 50mm centres (Fan DF1206BM)
If you want to use a different fan, contact me and I can happily modify the bolt hole centres and hole size.
Due to the gentle angle - you should not need any support, my Geeetech Prusa ProB i3 handled it perfectly.
Finished cover in position
Showing bolt pushed through existing hole to hold cover firmly in place
This is how I positioned it to print it. It did not need any support to print the overhang.
Fan size and hole centers for fan: Fan DF1206BM if you want to use a different fan, contact me and I can happily modify the bolt hole centres and hole size.