Printer does not turn on or keeps turning off

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If your printer doesn't turn on, or it keeps turning off during preheating, the most common causes are either a wrong voltage on the PSU or a blown fuse.

The printer does not turn on

If your printer does not turn on at all, then there might be a more serious problem present. Try the following steps:

• Turn the printer off and disconnect the power cord.
• Check all the wiring for broken cables. In some cases, overtightening the zip-ties can damage the wire insulation and cause a short.
• Check the wiring of your RAMBo board. Make sure that the PSU cables are properly plugged.
• Use the appropriate guide to check if any of the fuses in your printer are blown
  • Blown Fuse (MK3/MK3S/MK3S+)
  • Blown Fuse (MK2S/MK2.5/MK2.5S)
  • Blown Fuse (MINI).

MK2S / MK2.5 / MK2.5S

If your printer happens to power off during the initial preheating process, there's usually no serious damage. Most likely you just have the voltage switch set to 220V in a 110V power environment.

1. Turn the printer off and remove it from the power source.
2. Find the AC voltage switch for 110v or 220v on the PSU.
   

   

3. Make sure that the rocker is switched to your local voltage setting.
4. Try to turn the printer on again.

Checking status-LED on the PSU

Every PSU has a green indicator LED to show whether it is active or not.

The silver PSU has this located inside its case, seen through the metal cover, in the bottom-left (purple arrow).

The black Delta PSU has this LED hidden behind the cover of its terminals. Remove the two screws on the cover (green circles) to reveal the terminals, for probing with a multi-meter, and the green indicator-LED (orange arrow).