THE MAC MINI is under fire for shipping with what some claim to be a defective DVI > VGA converter. Numerous filings on Apple"s web support board disclose the problems of irate Mini-buyers, who are finding that their Mac mini looks simply dreadful when connected up to a CRT. Brightness is too low, buyers say, and sometimes the display fails to show up at all. Calls to Apple have so far yielded a "Your monitor is incompatible, there"s nothing wrong with our product" response from Apple"s technical yes-men.