First, which fuse on the RAMBo?
- The HOTEND FUSE, labeled F3, is the tiny 5A fuse beside the power input to the RAMBo and located closer to the large 15A auto fuse.
- The MOTOR FUSE is the tiny 5A fuse, labeled F2, is located near the capacitor and farthest away from the large 15A auto fuse.
- The BED FUSE is the large 15A auto fuse, labeled F4, is located close to where you hook up bed heating wires.
**Be very carefule not to damage the tiny fuse holders when removing the fuse. They are fragile **
Power off and unplug machine before working with electrical.
If you blew a HOTEND fuse, F3?
- check for short circuits in wiring and heater cartridge wires, etc.
- test for proper ohm reading, old bowden ~3.4ohm, HE280 ~3.9ohm
- it's rare, but possible for heating elements to give an ohm reading, but short after power is applied (just something to keep in mind)
- stray wires or touching hotend heat sink
If you blew a MOTOR fuse, F2?
- This is not very common. Check for stray wires at connectors
- check for loose connections or damaged wires to the motor
- check motor for free rotation
- check stepper motor coils (both coils) for resistance to make sure there isn't a short circuit
If you blew a BED fuse, F4?
- check for short circuits in wiring
- check solder joints on bottom of heat bed
- check bed for an ohm reading (not short circuit)
electrical power circuit