Hi there,

I have a Prusa i3 Hephestos and the printer was working fine for years. From one day to the other, I have the following issue.

I still can:
- move to the home position
- level the plate
- print objects via USB (!!!)

BUT I can not print any longer from the SD card. As soon as I select the .gcode-file, the Prusa reboots! Yes, not funny.

I have:
… formatted the SD card
… tried another SD card
… tried several other .gcodes-files
… up- and downgraded the firmware

But all without any luck. Do I have a power supply issue or defect display-card-unit? Any other ideas?

Many Thanks!

Sounds like Atmegas 5V onboard regulator gave up. You can use a 1A USB phone charger, if you don't want to connect it to your PC permanently.

Thanks! Where is this regulator located (RAMPS 1.4 or LCD-unit)? So you're telling me that when I connect a 1A USB phone charger (and power supply) I could print from the SD card again?

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Where is this regulator located (RAMPS 1.4 or LCD-unit)?

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Atmegas 5V onboard regulator

Does that answer your question? The LCD is fed by the onboard regulator and some graphic LCDs are known to draw to much current. Some older SD-cards also have this problem.

The 5 volt regulator is on the arduino board

It was the external power adapter/device (12V 8.0A)… replaced and works like a charm again… thanks!