Wind speed sensor is slow

[Bob K]

My ST40 wind speed indicator always reads significantly lower wind speed than actual.  The cups turn slower than on other boats, so I am sure the problem is in the sending unit.  I hope I can clean or lubricate it to restore proper operation.   A search of this forum shows at least one other has had same problem, but not known if ever resolved.  Are there any pearls of wisdom out there to share with me?
Thanks,
Bob

[Ron Hill]

Bob : Take your mast unit off and have it checked.  It sounds as though one or more bearings needs to be replaced. 
Data Marine repair can be found on line.   

[Tom Glennon]

Here is the link to the Datamarine repair man.
They have two different locations, as "DMI" is the parent, and Datamarine is the older instruments.

dmifix@sea-dmi.com

Hope it's an easy fix!  I am experiencing a similar fate.... reading slower than actual conditions. I dropped mine off this morning for servicing.