When exchanging the mainboard of my Ultimaker Original, I found the new (unoriginal) mainboard to have a condensator that is quite a little higher than on the original, which means the fan duct doesn't fit any more.
I read somewhere that those A4988 stepper motor drivers don't have to be actively cooled, but a heatsink will be sufficient:
After testing the theory I found the heatsinks to be really hot, but not too hot to touch. Sadly I do not have any means of temperature measurement other than my fingers...
How hot do they normally get, when should I abort printing and look for a different solution?
Are there any good solutions other than the original cooler & cooling duct?