Printer heatbed turns off when build plate is lowered onto it. - Hardware, firmware and software help https://forum.prusa3d.com/forum/english-forum-original-prusa-i3-mk3-5s-hardware-firmware-and-software-help/printer-heatbed-turns-off-when-magnetic-plate-is-lowered-onto-it/ Prusa3D Forum Discussion Board en-US Sat, 06 Jun 2026 17:07:56 +0000 wpForo 60 Printer heatbed turns off when build plate is lowered onto it. https://forum.prusa3d.com/forum/english-forum-original-prusa-i3-mk3-5s-hardware-firmware-and-software-help/printer-heatbed-turns-off-when-magnetic-plate-is-lowered-onto-it/#post-741848 Sat, 22 Mar 2025 21:44:50 +0000 Been having a lot of resets lately. (Like, all the time.)

Took the cap off the bed attachment header and attached a voltmeter.  With the build plate off the heater bed, after setting the machine to preheat for PLA, the bed gets 24-ish volts and starts heating up.

But as soon - like immediately and always - as I lower the build plate onto the bed, the voltage drops to zero.

Help?

]]> Hardware, firmware and software help Cranberryhiker https://forum.prusa3d.com/forum/english-forum-original-prusa-i3-mk3-5s-hardware-firmware-and-software-help/printer-heatbed-turns-off-when-magnetic-plate-is-lowered-onto-it/#post-741848