Most scanning systems have pots that are used to set the scan amplitude. 
Simply swapping connectors to x-y motors may reveal a defective scan 
motor but you have to watch out if the loop gain of the servo is 
critical as the swapped motor may break into oscillation. I'd guess you 
need a service book to find the connections and signals to 'tune up' the 
motor response. If the Biorad 1024 scanner uses the commercial scan 
boards (e.g General Scanning) some tech. info may be available on the web.

Good luck.

Mark

Michael Hendrickson wrote:
> Hello,
>
> We recently replaced the power supply (all five subunits) for our
> Bio-Rad 1024 control tower.  After starting the system, there was an
> obvious distortion along the X-dimension in all images.  It appears
> that the X galvo is zoomed by a factor of ~3.6, resulting in
> magnification along only the X-dimension.  The characteristic scanning
> sound produced with a zoom factor of 1 (no zoom) is not present,
> suggesting that indeed the galvo is set to a zoom of ~3.6.  An image
> of 15-micron green beads collected with the system can be seen here:
> http://www.keck.bioimaging.wisc.edu/15umbeads.jpg.  All other aspects
> of the system work fine, including the zoom function, which allows
> zooming but maintains the distortion.  The software calibration
> settings do not appear to have changed.
>
> Any insights into the cause of the problem (and how to fix it) would
> be greatly appreciated.
>
> Thanks,
>
> Michael Hendrickson
> Assistant Manager
> W.M. Keck Laboratory for Biological Imaging
> University of Wisconsin-Madison
> www.keck.bioimaging.wisc.edu
>