Imported chinese scales

Hi guys
I have put together a cheap 3 axis DRO system using the imported
chinese scales but have noted that the X and Y scales can sometime
jump when other machinery is started up. The X axis can jump by.1"
but the Y axis can jump to a really high number, the same thing that
happens when a new battery is fitted.

Has anyone else experienced this. If so any advice for a possible
cure would be appreciated.

Cheers Dave