Epson 1660 Photo scanner serving problem

I have an Epson Perfection 1660 Photo scanner & the last time I fired it up
I got this sound like a machine gun going off & I noticed that the scan
assembly wasn't moving. . My immediate guess was that the rubber belt with
notches in it was not correctly catching it's gear wheel. I opened the
scanner & by unscrewing the motor assembly I was able to get the belt to
engage with the rubber belt. Once reassembled I then plugged the power
supply back in. Windows XP recognized that the scanner was attached & said
that it was ready for use & at the same time the scan assembly started to
move.

Then I noticed that I had a red light on at the front of the machine. I
tried using the software to see if it would scan, but all that happened was
that the software gave me an error message This time the scan assembly
didn't move. Looking further it seems as if the belt slots into the bottom
of the scan assembly. When power was re supplied the assembly started to
move to the front I heard a click sound. When the rubber belt is connected
should the assembly be at the front or back of the scanner? Is there likely
to anything else to do to ensure that the machine starts working correctly
again?
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Thanks in advance