RICHFIELD, Minn. –The Minnesota-based Best Buy chain of 1,000 tech stores plans to close 30 this year in the face of declining corporate revenue, according to the insider trade journal Retail Dive. The journal didn’t identify the stores being closed. The revenue issue is this: Down 3.8% to $43.8 million. In Minnesota already, the Shakopee and Blaine stores have been closed ,although the Blaine site is being refitted as a discount outlet.