Xerox Phaser Makes Strange Noise Will Not Start

We just received a phaser 1235 from one of our locations that closed.
The unit was missing all of the toners so I added new toner and
powered the unit up for a check. The unit powers up and scrolls
through the messages on the front, but then it make a loud 'klunk,
klunk, klunk' noise and the unit almost jumps up and down on the
table. I have checked the drums, imaging unit, and toners to make
sure they are seated, but I am still getting this noise every time I
power up. Needless to say the unit shows an error after it makes this
noise and will not do anything else as it says check unit. The noise
that the unit makes sounds like a car going over the spaces in a old
wooden bridge. The unit is not under warranty and we are trying to
determine if we should keep the unit as it only has 15 prints on it.

Thank you in advance for your replies and assistance in this matter.