Voltage Regulator "U2" U2MC7805ABD2T -very hot/Voltage drops

Vertex 3D Printer Vertex - Wiring and electronics
1

Yesterday my printer stopped working.

When turning on the printer, the display only shows some stripes for a second or so and than the Brightness lowers down and display flickers a bit. The Leds on the Mainboard are all shining red.

I began searching for the defect and noticed the Firmware is sill flashable, so the Atmega must be functioning. Or not? There’s no component on the mainboard which looks defect - like burnt or molten parts.

I noticed the Voltage Regulator (15V to 5V 1A) becomes very hot after a few seconds. I measured from output of the Voltage Regulator to ground. The Voltage drops from 5V to ~3.6V. The same time the Voltage drops, the display brightness is dropping too. https://www.dropbox.com/s/mw4wnigdc6s8mna/K8400%203D%20Printer%20Technical%20Doc.pdf?dl=0 -> “U2”

Does anybody has an idea if the Voltage Regulator is the defect part? Is there a chance to get the printer working again when I replace the Regulator.

Any Ideas, anybody heard of similar problems ?

Best regards

Morvling

2

OK, read some more posts. I’ve checked the Voltage with all Steppers and Stepper-Drivers unmounted.

Seems possible that the Voltage Regulator is is getting so hot (and regulating down) because of Overcurrent because of one of the other parts. How can i figure out if - and where the overcurrent comes from ?

Best regards

Morvling