Representatives from Capital Group Properties,  the Southborough-based development company seeking to redevelop the 129 Parker St. site in Maynard, are holding an informational open house on Feb. 6  from 6  to 8:30 p.m.  at the site. The site was formerly home to Digital Equipment Corp.  Capital Group Properties has begun demolition of some buildings there and has proposed building a mixed-use development of around 700,000 square feet.