The Celtics moved their TV coverage from WBZ-TV to WLVI-TV, or Channel 56 as we called it prior to the 1985-1986 championship season. And unless you had cable TV (We didn't) we could watch all the Celtics away games on Channel 56, but only the home games if they were on national TV, which I believe was CBS at the time.
Gil Santos and Bob Cousy were the broadcast duo for four years with Mike Crispino replacing Santos for the 1989-90 season. Here's a little walk down 1980's memory lane for today's throwback.
In the 1990's the Celtics changed broadcast TV networks a few times, while Mike Gorman and Tommy Heinsohn continued to cover home games for Sportschannel on paid cable.