misbehaving Starrett digital caliper

["Richard P. Welty" <rwelty@suespammers.org>]

i have a Starrett Digital Caliper (it's NYR Region SCCA's caliper,  
actually,
model number is 721A-6/150). this past weekend at a race at lime  
rock, it
started acting up. the display no longer alters when the slide moves
(e.g., zero it, move the slide, and the display is stuck at 0.0000).
occasionally, the ERR 04 display comes up claiming that the slide is  
being
moved too quickly, regardless of the speed i'm sliding it at.

anyone know what the prospects are of fixing this, or is this likely to
be a toss-and-replace situation?

thanks,
   richard