asked Feb 19, 2020 at 6:50am
Hp HP DesignJet 750C

Switch power off check paper path

When powered up the platen does not move and the print head moves slowly from left to right then quickly returns to the left. Then I get the error message. There is nothing in the paper path, no paper loaded.

I removed the right side cover, removed the worm gear and the platen and motor both move freely. I moved the print head to the right, powered up the machine and checked the led located on the bottom right side of the print head but it's not glowing.

Bad LED? If I manually start to turn the platen it spins forward about 1.5 revolutions, stops suddenly and then reverses about 1 rotation. Bad main logic board?