problemas con smalldatetime !!

[Andres95]

En la ayuda de SQL Server puedes confirmar que el smalldatetime no te da la funcionalidad que requieres (almacenar segundos).

Código:

The smalldatetime data type stores dates and times of day with 
less precision than datetime. SQL Server stores smalldatetime 
values as two 2-byte integers. The first 2 bytes store the number 
of days after January 1, 1900. The other 2 bytes store the number 
of minutes since midnight. Dates range from January 1, 1900, 
through June 6, 2079, with accuracy to the minute.

Saludos!