Quote Originally Posted by jfkansas View Post
The fan underneath the printer is left over from a MakerBot Rep 1 attempt at a patch for an overloaded voltage regulator., and the fan didn't fix it. The original open source plans still had the fan and that is what the Chinese copied. There is no reason for the fan underneath the printer, and I have had one hooked up in over a year, on either printer. The stepper drivers the fan blows on run at about 20% of their rated capability so they are practically idling.
I can't run mine without the fan underneath, it just cooks under there - but it does run dual extrusion most of the time so maybe the extra driver? who knows, all I know is that if I use my Temp gun and point it at anything electronic and I see 70c+ then I know it's time for a fan and it hits 70c easy in my chamber underneath - don't even need a heated bed half the time for PLA at all.