Have in stalled 40 mm 12 v fan for PLA printing. Fan appeared to work for a bit, but now after a few prints with it it will not turn. Have done the following as a test.
Slic3r “fan always on” at 75% = no good
Gcode M106 S193 at start of print = no good
tested fan with 7.2 v battery pack with current of 56 mA = fan spins great
multimeter to terminals on rambo = 9.2 v at 75%
multimeter test of current on rambo = 12 mA
Is the lower amperage my problem and if so how do I fix. Have replaced the fuse already thinking that was a problem.
You can manually turn on the fan by sending the gcode command M106 to turn it on full, and M107 to turn it off. Does the command operate the fan appropriately? Would you mind posting your Slic3r config (Slic3r > File > Export)?
In any printer host software, that would run on a separate computer (Printrun, Repetier-Host, etc) you can send manual gcode commands. In Pronterface (Printrun) in the lower right hand side of the screen you can send the following command “M106 S123” to turn on the fan, at 50% speed. If you are using the graphical lcd controller, you would simply use the menu entries.
Try a slightly lower speed (S200), and then manually give the fan a push. If it starts to spin, then you know the power is okay. Its just that the fan you have may not like to be run on PWM.