Repairing PM500-1L stage (25mm travel, 50mm/sec speed, 0.025micron precision)

Sergei P. Skorobogatov
sps32 (at)

Manufacturer: Newport Corporation, USA

Date of production: January 1997

General information:<wo=Motion%20Control

This is another Newport ultra-precision compact linear stage I recently acquired. Unfortunately, as it always happens when you get a second-hand mechanical or optical equipment, it was in a poor working condition and cannot be used without prior repair. First, the moving platform was loosen and the handle did not affect its movement at all. Second, the handle was scratching the stage body if turned, thus increasing the load on the motor and producing unpleasant noise.

PM500-1L PM500-1L PM500-1L
I decided to fix the handle first. There were two ways for doing this - either by displicing the motor or by shifting the handle. The motor was already in the farest position, so it cannot be moved further toward the handle. Therefore, I had to move the handle. I cut a piece of sticky aluminium tape and attached it to the shaft on which the handle was put. That helped to put it away from the stage body.

PM500-1L PM500-1L PM500-1L
The next step was to figure out what happened to the moving part. First, I disassembled the stage. Then, by looking at the worm shaft, I noticed that the part to which the moving platform was screwed, went off the special nut. As a result, nothing was holding the stage in the position.

PM500-1L PM500-1L PM500-1L
Fixing that was not an easy task, because of the construction of that connector. To attach the nut to the stage holder it had to be unscrewed first. Then the holder pushed onto it and the nut with two springs and washer asssembled together. After that the holder was pushed further until the end.

PM500-1L PM500-1L PM500-1L
Finally, the fixing block was screwed to the holder at the angle which provided minimal backlash of the movement and at the same time being not too tight for easy move. Assembled and tested stage shown very good performance and smooth travel.

Sergei Skorobogatov <Sergei.Skorobogatov (at)> <Sergei.Skorobogatov (at)>
created 20-10-2004 -- last modified 06-11-2004 --